gmat geometry - everything you need to know

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GMAT Geometry - Everything you need to know This slideshow features screenshots from GMAT Prep Now’s entire Geometry module (consisting of 42 videos). It covers every key concept you need to know about GMAT Geometry. It also includes 27 practice questions. www.GMATPrepNow.com

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Page 1: GMAT Geometry - everything you need to know

GMAT Geometry - Everything you need to know

This slideshow features screenshots from GMAT Prep Now’s entire Geometry module (consisting of 42 videos). It covers every key concept you need to know about GMAT Geometry. It also includes 27 practice questions.

www.GMATPrepNow.com

Page 2: GMAT Geometry - everything you need to know

GMAT Geometry - Everything you need to know

www.GMATPrepNow.com

Note: since these slides are just snippets of a full-length video course, there may be times when you’re unable to glean all the relevant information from a particular screenshot. If, at any time, you’d like to watch the entire video on a certain topic, just click on the link at the top of that page, and you’ll be taken that that particular video.

Page 3: GMAT Geometry - everything you need to know

GMAT Geometry - Everything you need to know

If you enjoy this unique learning format, let us know, and we’ll add similar resources to our SlideShare page

Page 5: GMAT Geometry - everything you need to know

Lines and Angles

l

line: a straight path that extends without end in both directions

(watch the entire video here)

Page 6: GMAT Geometry - everything you need to know

Lines and Angles

l

A

B

AB: line segment

AB: length of line segment AB (e.g., DE=7)

line: a straight path that extends without end in both directions

(watch the entire video here)

Page 7: GMAT Geometry - everything you need to know

Lines and Angles

55

A

BC

55

55

ABC

CBA

55x

x

angle: intersection of 2 lines

: measured in degrees or radians

(watch the entire video here)

Page 8: GMAT Geometry - everything you need to know

Lines and Angles

180

Angles on a line add to 180°

a cb

180a b c

70x

70 180

110

x

x

(watch the entire video here)

Page 9: GMAT Geometry - everything you need to know

Lines and Angles

90

right angle: angle of 90 degrees

P

PQ is perpendicular to AB

BA Q

(watch the entire video here)

Page 10: GMAT Geometry - everything you need to know

Lines and Angles

bisect: cut or divide into 2 equal pieces

J

JK bisects AB

BA

A

BC

bisect s ABC

bisector is the of ABC

line l is the perpendicular bisector of AB

BA

K

l

(watch the entire video here)

Page 11: GMAT Geometry - everything you need to know

Lines and Angles

ac

x

x

b

d

- a and c are vertical angles

- a and c are opposite angles

- a and c are vertically opposite angles

- b and d are opposite angles

Opposite angles are equal

y

y

Aside: 180x y

(watch the entire video here)

Page 12: GMAT Geometry - everything you need to know

Lines and Angles

w 50

yx

(watch the entire video here)

Page 13: GMAT Geometry - everything you need to know

Lines and Angles

w 50

yx

50x 50 180

130

w

w

130y

Opposite angles are equal

Angles on a line add to 180°

(watch the entire video here)

Page 14: GMAT Geometry - everything you need to know

Lines and Angles

1

2

If two lines do not intersect, they are parallel

1 2

(watch the entire video here)

Page 15: GMAT Geometry - everything you need to know

Lines and Angles

1

2

If two lines do not intersect, they are parallel

y

y

y

y

x

Note: 180x y

x

x

x

1 2

(watch the entire video here)

Page 16: GMAT Geometry - everything you need to know

Lines and Angles

Opposite angles are equal

Angles on a line add to 180°

1

2

1 2

y

y

y

y

x

x

x

x

(watch the entire video here)

Page 17: GMAT Geometry - everything you need to know

Practice Question

A) 10

B) 17.5

C) 22

D) 35

E) 42.5

If l1 and l2 are parallel, then x =

1

2

3 5x

15x

Note: Figure not drawn to scale

Page 18: GMAT Geometry - everything you need to know

A) 10

B) 17.5

C) 22

D) 35

E) 42.5

If l1 and l2 are parallel, then x =

1

2

3 5x

15x 3 5x

15 3 5 180

4 10 180

4 170

42.5

x x

x

x

x

Note: Figure not drawn to scale

Practice Question (watch the entire video here)

Page 19: GMAT Geometry - everything you need to know

Triangles – Part I (watch the entire video here)

Page 20: GMAT Geometry - everything you need to know

Triangles – Part I

A

B Cw x

y180w x y

Angles in a triangle add to 180°

(watch the entire video here)

Page 21: GMAT Geometry - everything you need to know

Triangles – Part I

A

B C21

44180w x y

Angles in a triangle add to 180°

w

(watch the entire video here)

Page 22: GMAT Geometry - everything you need to know

Triangles – Part I

A

B C21

44180w x y

Angles in a triangle add to 180°

w

180

180

1

2 4

5

4

1

1

65

w

w

w

(watch the entire video here)

Page 23: GMAT Geometry - everything you need to know

Triangles – Part I

A

B Cw x

y

The longest side is opposite the largest angle

The shortest side is opposite the smallest angle

A

B

C

a

b

c

If then a b c A B C

(watch the entire video here)

Page 24: GMAT Geometry - everything you need to know

Triangles – Part I

1

The sum of the lengths of any two sides of a triangle must be greater than the third side.

2 4

1 2

1 42

4

(watch the entire video here)

Page 25: GMAT Geometry - everything you need to know

Triangles – Part I

If a triangle has sides with lengths 3 and 7, what lengths are possible for the third side?

3 7

The sum of the lengths of any two sides of a triangle must be greater than the third side.

(watch the entire video here)

Page 26: GMAT Geometry - everything you need to know

Triangles – Part I

If a triangle has sides with lengths 3 and 7, what lengths are possible for the third side?

7

third side 73 37

3 4

rd difference between other 2 sides 3 side sum of other 2 sides

Given lengths of sides A and B

rd 3 sideA B A B

(watch the entire video here)

Page 27: GMAT Geometry - everything you need to know

Triangles – Part I

Given lengths of sides A and B

rd 3 sideA B A B

Angles in a triangle add to 180°

A

B

C

a

b

c

If then a b c A B C

The sum of the lengths of any two sides of a triangle must be greater than the third side.

(watch the entire video here)

Page 28: GMAT Geometry - everything you need to know

Is w > x ? Q

P

w x

y

R

2) 3QR

1) 6PQ

Practice Question

A) Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient

B) Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient

C) BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient

D) EACH statement ALONE is sufficient

E) Statements (1) and (2) TOGETHER are NOT sufficient

Page 29: GMAT Geometry - everything you need to know

Q

P

w x

y

R

1) 6PQ

A

B

C

a

b

c

If then a b c A B C

2) 3QR

3

1&2)

6

Given lengths of sides A and B

rd 3 sideA B A B

3 9PR

E

6 3 36PR

Is w > x ? Is ?PR PQ

Practice Question (watch the entire video here)

INSUFFICIENT

INSUFFICIENT

INSUFFICIENT

Page 30: GMAT Geometry - everything you need to know

What is the value of x in terms of y ?

A) 65

B) 21

C) 22

D) 21

E) 22

y

y

y

y

y

x

y

2243

Practice Question

Page 31: GMAT Geometry - everything you need to know

(watch the entire video here) Practice Question

What is the value of x in terms of y ?

A) 65

B) 21

C) 22

D) 21

E) 22

y

y

y

y

y

x

y

2243

a

43 180ya

43 22 180xa

43 22 43

43 22 43

22

22

a x y

x y

x y

x y

a

Angles in a triangle add to 180°

Solution #1

Page 32: GMAT Geometry - everything you need to know

Solution #2

(watch the entire video here) Practice Question

What is the value of x in terms of y ?

A) 65

B) 21

C) 22

D) 21

E) 22

y

y

y

y

y

x

y

2243

158 x

180

158 18

1

0

22

22

22

58y

y x

y x

y x

y x

x

Angles on a line add to 180°

1

22 180

1

58

58

x

x

c

c

c x

158 180

22

y x

y x

Page 33: GMAT Geometry - everything you need to know

Assumptions and Estimation (watch the entire video here)

Page 34: GMAT Geometry - everything you need to know

Assumptions and Estimation

120

• Lines that appear straight can be assumed to be straight

(watch the entire video here)

Page 35: GMAT Geometry - everything you need to know

Assumptions and Estimation

120

60

• Lines that appear straight can be assumed to be straight

(watch the entire video here)

Page 36: GMAT Geometry - everything you need to know

• Do not make assumptions about angle measurements

x

Assumptions and Estimation (watch the entire video here)

Page 37: GMAT Geometry - everything you need to know

y

• y +x =180

• Both angles are greater than zero degrees

x

Assumptions and Estimation

(watch the entire video here)

Page 38: GMAT Geometry - everything you need to know

• Do not make assumptions about parallelism

1

2

1 2

Assumptions and Estimation (watch the entire video here)

Page 39: GMAT Geometry - everything you need to know

Problem Solving Questions

• Figures are drawn to scale unless stated otherwise

• Estimate to confirm calculations and guide guesses

x

40O

BE

A) 40

B) 50

C) 60

D) 70

E) 80

Assumptions and Estimation

C

DA

If is the center of the circle,and , what is the value of ?

OAB CD x

(watch the entire video here)

Page 40: GMAT Geometry - everything you need to know

Data Sufficiency Questions

• Figure conforms to information in question

• Figure does not necessarily conform to information in statements

• Avoid visual estimation

Assumptions and Estimation (watch the entire video here)

Page 41: GMAT Geometry - everything you need to know

Assumptions and Estimation

• Lines that appear straight can be assumed to be straight

• Angles are greater than zero degrees

• Do not make assumptions about angle measurements

• Do not make assumptions about parallelism

• Use visual estimation sparingly

(watch the entire video here)

Page 42: GMAT Geometry - everything you need to know

Geometry Strategies – Part I (watch the entire video here)

Page 43: GMAT Geometry - everything you need to know

Geometry Strategies – Part I

• Redraw figures

• Add all given information

• Add all information that can be deduced

• Add/extend lines

• Assign variables and use algebra

• Drawn to scale estimate to confirm calculations and guide guesses

• Drawn to scale estimate measurements to confirm or guess

(watch the entire video here)

Page 44: GMAT Geometry - everything you need to know

Triangles – Part II (watch the entire video here)

Page 45: GMAT Geometry - everything you need to know

Triangles – Part II

Isosceles triangle

• 2 equal sides, 2 equal angles

A

B

C

a

b

c

If then a b c A B C

40 40

100

x

x

(watch the entire video here)

Page 46: GMAT Geometry - everything you need to know

Triangles – Part II

38

(watch the entire video here)

Page 47: GMAT Geometry - everything you need to know

Triangles – Part II

38

38

104

(watch the entire video here)

Page 48: GMAT Geometry - everything you need to know

Triangles – Part II

38

38

104

40

(watch the entire video here)

Page 49: GMAT Geometry - everything you need to know

Triangles – Part II

38

38

104

40

x

x

40 180

2 40 180

2 140

70

x x

x

x

x

(watch the entire video here)

Page 50: GMAT Geometry - everything you need to know

Triangles – Part II

38

38

104

40

70

40 180

2 40 180

2 140

70

x x

x

x

x

70

(watch the entire video here)

Page 51: GMAT Geometry - everything you need to know

Triangles – Part II

A

B

C

Equilateral triangle

• 3 equal sides, 3 equal angles

60 60

60

(watch the entire video here)

Page 52: GMAT Geometry - everything you need to know

Triangles – Part II

A

B C

10

48

Area

- ft 2

- cm 2

- m 2

(watch the entire video here)

Page 53: GMAT Geometry - everything you need to know

Triangles – Part II

A

B C

base heightArea

2

10

48

Area

1Area base height

2

(watch the entire video here)

Page 54: GMAT Geometry - everything you need to know

Triangles – Part II

A

B C

base heightArea

2

10Area

15

3

2

10

34

8

altitude height

Area

(watch the entire video here)

Page 55: GMAT Geometry - everything you need to know

Triangles – Part II

10

4

8

A B

C

7.5

base heightArea

2

7A

.re

5a

15

4

2

Area

(watch the entire video here)

Page 56: GMAT Geometry - everything you need to know

Triangles – Part II

A

B

C60 60

60

2

3 sideArea

4

(watch the entire video here)

Page 57: GMAT Geometry - everything you need to know

Triangles – Part II

A

B

C60 60

60

2

3 sideArea

4

6 6

6

2

3Area

4

3 36

4

9 3

6

(watch the entire video here)

Page 58: GMAT Geometry - everything you need to know

Triangles – Part II

60 60

60

The altitudes of isosceles triangles and equilateral triangles bisect the base.

(watch the entire video here)

Page 59: GMAT Geometry - everything you need to know

Triangles – Part II

• An isosceles triangle has 2 equal sides and 2 equal angles

• An equilateral triangle has 3 equal sides and 3 equal angles (60° each)

base heightArea

2

2

3 sideArea

4

• The altitudes of isosceles triangles and equilateral triangles bisect the base

(watch the entire video here)

Page 60: GMAT Geometry - everything you need to know

Practice Question

A) 27.5

B) 55

C) 62.5

D) 70

E) 125

If AB and CD are parallel, and AB = BC, then x =

A

B

C

D

x

55

Note: Figure not drawn to scale

Page 61: GMAT Geometry - everything you need to know

Practice Question

A) 27.5

B) 55

C) 62.5

D) 70

E) 125

If AB and CD are parallel, and AB = BC, then x =

Note: Figure not drawn to scale

A

B

C

D

x

5555

55

180

110 18

5 5

70

5 5

0

x

x

x

(watch the entire video here)

Page 63: GMAT Geometry - everything you need to know

Right Triangles

leg1

• Right triangle: triangle with right (90°) angle

• The hypotenuse is the longest side

leg2

2 2 2

1 2leg leg hypotenuse

2 2 2a b c

a

bc

2 2 2a b c

a

bc 2 2 2a b c

a

bc

(watch the entire video here)

Page 64: GMAT Geometry - everything you need to know

Right Triangles

8

6

x

(watch the entire video here)

Page 65: GMAT Geometry - everything you need to know

Right Triangles

2 2 2a b c

a

bc

8

6

x

2 2 2

2

2

8 6

64 36

100

100

10

x

x

x

x

x

(watch the entire video here)

Page 66: GMAT Geometry - everything you need to know

Right Triangles

2 2 2a b c

a

bc

8

6

x

2 2 2

2

2

8 6

64 36

100

100

10

x

x

x

x

x

6

4x

(watch the entire video here)

Page 67: GMAT Geometry - everything you need to know

Right Triangles

2 2 2a b c

a

bc

8

6

x

2 2 2

2

2

8 6

64 36

100

100

10

x

x

x

x

x

2 2 2a b c

a

bc

6

4x

2 2 2

2

2

4 6

16 36

20

20

2 5

x

x

x

x

x

4 5

2 5

x

x

(watch the entire video here)

Page 68: GMAT Geometry - everything you need to know

Right Triangles

• 3-4-5

4

35

• 5-12-13

12

135

• 8-15-17

2 2 23 4 5

2 2 25 12 13

• 7-24-25

Pythagorean triples: A set of 3 integers that can be the sides of a right triangle

(watch the entire video here)

Page 69: GMAT Geometry - everything you need to know

Right Triangles

8x 17

15

• 8-15-17

2 2 215 17x

2 2 2a b c

(watch the entire video here)

Page 70: GMAT Geometry - everything you need to know

Right Triangles

• 3-4-5

• 5-12-13

• 8-15-17

• 7-24-25

6-8-10 9-12-15 12-16-20

10-24-26

4

35

4 7 28

5 7 35 213 7x

. . .

. . .

. . .

2 corresponding sides required to use Pythagorean triples

. . .

(watch the entire video here)

Page 71: GMAT Geometry - everything you need to know

Right Triangles

• 3-4-5

• 5-12-13

• 8-15-17

• 7-24-25

6-8-10 9-12-15 12-16-20

10-24-26

. . .

. . .

. . .

50

4

35

Enlarged by factor

of 10

50

24

725 Enlarged

by factor of 2

40

30

48

14

2 corresponding sides required to use Pythagorean triples

. . .

(watch the entire video here)

Page 72: GMAT Geometry - everything you need to know

Right Triangles

• 3-4-5

• 5-12-13

• 8-15-17

• 7-24-25

6-8-10 9-12-15 12-16-20

10-24-26

. . .

. . .

. . .

34

x

. . .

(watch the entire video here)

Page 73: GMAT Geometry - everything you need to know

Right Triangles

• 3-4-5

• 5-12-13

• 8-15-17

• 7-24-25

6-8-10 9-12-15 12-16-20

10-24-26

. . .

. . .

. . .

3

x

4

2 2 2a b c

2 2 2

2

2

3 4

9 16

7

7

x

x

x

x

. . .

(watch the entire video here)

Page 74: GMAT Geometry - everything you need to know

Right Triangles

2 2 2a b c

a

bc

• Watch out for Pythagorean triples (and their multiples)

3-4-5

5-12-13

8-15-17

7-24-25

(watch the entire video here)

Page 75: GMAT Geometry - everything you need to know

Practice Question

AA) 2 3

B) 2 5

C) 30

D) 4 3

E) 4 5

B

The height of this rectangle is twice its width. If the distance

between points A and B is , what is the rectangle’s height? 60

Page 76: GMAT Geometry - everything you need to know

Practice Question

AA) 2 3

B) 2 5

C) 30

D) 4 3

E) 4 5

x

2x

22 2

2 2

2

2

2 60

4 60

5 60

12

12

4 3

2 3

x x

x x

x

x

x

x

x

B

60

2 2 2a b c

2

4 3

2 2 3x

The height of this rectangle is twice its width. If the distance

between points A and B is , what is the rectangle’s height? 60

(watch the entire video here)

Page 77: GMAT Geometry - everything you need to know

Practice Question

A) 21

B) 9

C) 2 21

D) 149

E) 3 21

If the rectangular box shown here is 6 inches wide, 8 inches long and 7

inches high, what is the distance, in inches, between points A and B ?

B

A

8

6

7

Page 78: GMAT Geometry - everything you need to know

A) 21

B) 9

C) 2 21

D) 149

E) 3 21

B

A

8

6

7

If the rectangular box shown here is 6 inches wide, 8 inches long and 7

inches high, what is the distance, in inches, between points A and B ?

10

x7

A

B

10

x

2 2 2a b c 2 2 2

2

2

10 7

100 49

149

149

x

x

x

x

Practice Question (watch the entire video here)

Solution #1

Page 79: GMAT Geometry - everything you need to know

Practice Question

A) 21

B) 9

C) 2 21

D) 149

E) 3 21

If the rectangular box shown here is 6 inches wide, 8 inches long and 7

inches high, what is the distance, in inches, between points A and B ?

A

B

wx

y

2 2 2AB w x y

2 2 28 6 7

64 36 49

149

AB

B

A

8

6

7

(watch the entire video here)

Solution #2

Page 80: GMAT Geometry - everything you need to know

Special Right Triangles

45-45-90 triangle

1

45

2

2 1.445

1

leg : leg : hypotenuse

1 : :

x : :

1

x 2x

2

30-60-90 triangle

1

30

602

3

3 1.7

3

leg : leg : hypotenuse

1 : : 2

3xx : : 2x

(watch the entire video here)

Page 81: GMAT Geometry - everything you need to know

Special Right Triangles

1230

x

y

(watch the entire video here)

Page 82: GMAT Geometry - everything you need to know

Special Right Triangles

1230

x

y 30

601

2

3

60

enlargement factor: 6

(watch the entire video here)

Page 83: GMAT Geometry - everything you need to know

Special Right Triangles

1230

x

y 30

601

2

3

60

enlargement factor: 6

61

6

x

3

6 3

6y

(watch the entire video here)

Page 84: GMAT Geometry - everything you need to know

Special Right Triangles

5 2

x

5 2

(watch the entire video here)

Page 85: GMAT Geometry - everything you need to know

Special Right Triangles

5 2

x

5 2

45

12

451

45

45

enlargement factor:

2

5 4

5

2

2

10

5x

5 2

(watch the entire video here)

Page 86: GMAT Geometry - everything you need to know

Special Right Triangles

45

45

60 60

30

Square Equilateral Triangle

Watch out for special right triangles “hiding” in squares and equilateral triangles

(watch the entire video here)

Page 87: GMAT Geometry - everything you need to know

Special Right Triangles

45

12

451

30

601

2

3

(watch the entire video here)

Page 88: GMAT Geometry - everything you need to know

Practice Question

A) 3 2

B) 2 6

C) 4 3

D) 6 2

E) 6 3 B

A

C

D

If , 6 and 105 , then AD BD AB ABC x

Note: Figure not drawn to scale

x

Page 89: GMAT Geometry - everything you need to know

Practice Question

A) 3 2

B) 2 6

C) 4 3

D) 6 2

E) 6 3 B

A

C

D

If , 6 and 105 , then AD BD AB ABC x

Note: Figure not drawn to scale

45

45

60

30

x

45

1

451

enlargement factor: ? 6

2

266

2

30

60 2

3

6

2

1

2

12 2

2 2

12 2

2

2

6 2

6x

(watch the entire video here)

Page 90: GMAT Geometry - everything you need to know

Similar Triangles (watch the entire video here)

Page 91: GMAT Geometry - everything you need to know

Similar Triangles

Similar triangles have the same 3 angles in common

40 20120

40 20

120

With similar triangles, the ratio of any pair of corresponding sides is the same

wa

b c xy

a

w

b c

x y

(watch the entire video here)

Page 92: GMAT Geometry - everything you need to know

Similar Triangles

**

x

5 7

9

6

(watch the entire video here)

Page 93: GMAT Geometry - everything you need to know

Similar Triangles

**

x

5 7

9

With similar triangles, the ratio of any pair of corresponding sides is the same

5

5

63

6

5

3

5

7 9

7

9

x

x

x

x

6

(watch the entire video here)

Page 94: GMAT Geometry - everything you need to know

Similar Triangles

Similar triangles have the same 3 angles in common

40 20120

40 20

120

With similar triangles, the ratio of any pair of corresponding sides is the same

wa

b c xy

a

w

b c

x y

(watch the entire video here)

Page 95: GMAT Geometry - everything you need to know

Practice Question

If , then ABC BCD x

Note: Figure not drawn to scale

BA

C D

8

10 12

5 x

E

A) 4

25B)

6

C) 6

36D)

5

E) 24

Page 96: GMAT Geometry - everything you need to know

Practice Question

If , then ABC BCD x

Note: Figure not drawn to scale

BA

C D

x

E

❤ With similar triangles, the ratio of any pair

of corresponding sides is the same

12

5

5

12 10

12 1

50

50

12

25

6

0

x

x

x

x

x

A) 4

25B)

6

C) 6

36D)

5

E) 24

8

10 12

5

(watch the entire video here)

Page 98: GMAT Geometry - everything you need to know

Quadrilaterals

Angles in a quadrilateral add to 360°

A

D C

w

x

y360w x y z

B

z

(watch the entire video here)

Page 99: GMAT Geometry - everything you need to know

Quadrilaterals

square

rectangle

trapezoid

parallelogram

rhombus

(watch the entire video here)

Page 100: GMAT Geometry - everything you need to know

Quadrilaterals

parallelogram

opposite sides parallel

rectangle

opposite sides parallel

all angles are 90

rhombus

opposite sides parallel

all sides are equal

square

opposite sides parallel

(watch the entire video here)

Page 101: GMAT Geometry - everything you need to know

Quadrilaterals

trapezoid

2 sides parallel

(watch the entire video here)

Page 102: GMAT Geometry - everything you need to know

Quadrilaterals

Rhombus (and square)

• diagonals are perpendicular bisectors

Rectangle (and square)

• diagonals are equal length

A

D C

B

AC BD

(watch the entire video here)

Page 103: GMAT Geometry - everything you need to know

Quadrilaterals

square rectangle

trapezoid

area base height

base base

height height

base2

base1

height

1 2base basearea height

2

average of bases height

parallelogram rhombus

base

height

base

height

(watch the entire video here)

Page 104: GMAT Geometry - everything you need to know

Quadrilaterals

rhombus

1 2diagonal diagonalarea

2

4

7

area2

28

2

14

4 7

(watch the entire video here)

Page 105: GMAT Geometry - everything you need to know

Quadrilaterals

Angles in a quadrilateral add to 360°

parallelogram

opposite sides parallel

rectangle

opposite sides parallel

all angles are 90

rhombus

opposite sides parallel

all sides are equal

square

opposite sides parallel

trapezoid

2 sides parallel

area base height

(watch the entire video here)

Page 107: GMAT Geometry - everything you need to know

Polygons

Polygon: Closed figure formed by 3 or more line segments

(watch the entire video here)

Page 108: GMAT Geometry - everything you need to know

Polygons

“polygon” “convex polygon” (all interior angles less than 180°)

(watch the entire video here)

Page 109: GMAT Geometry - everything you need to know

Polygons

b

a

180a b c

Triangle

Quadrilateral

Pentagon

c

b

a

c

d360a b c d

b

a

cd 540a b c d e

e

Hexagon

b

a

cd 720a b c d e f

ef

(watch the entire video here)

Page 110: GMAT Geometry - everything you need to know

Polygons

The sum of the interior

angles in an N-sided polygon

is equal to 180 2N

6

1

23

4

5

Octagon

sum of angles 180 2

8180 2

180

10

6

80

N

(watch the entire video here)

Page 111: GMAT Geometry - everything you need to know

Polygons

Regular polygon: equal sides and equal angles

regular pentagon

(watch the entire video here)

Page 112: GMAT Geometry - everything you need to know

Polygons

• Polygon: Closed figure formed by 3 or more line segments

• “polygon” “convex polygon” (all interior angles less than 180°)

Triangle Quadrilateral

Pentagon Hexagon

• Regular polygon: equal sides and equal angles

The sum of the interior

angles in an N-sided polygon

is equal to 180 2N

(watch the entire video here)

Page 114: GMAT Geometry - everything you need to know

Circles

Circle: set of points that are equidistant from a given point

center

A

B

C

E

D

diameter u2 radi s

arc

- “arc CDE ”

- “minor arc CE ”

(watch the entire video here)

Page 115: GMAT Geometry - everything you need to know

Circles

circumference 2 radius

2 r

Circumference 3.14

3

22

7

circumference diameter

d

(watch the entire video here)

Page 116: GMAT Geometry - everything you need to know

Circles

circumference 2 r

Circumference

circumference 2

16 feet

16 3

48 f

8

eet

8 ft

(watch the entire video here)

Page 117: GMAT Geometry - everything you need to know

Circles

Area

2area r

2

2

area

6

8

4 ft

8 ft

(watch the entire video here)

Page 118: GMAT Geometry - everything you need to know

Circles

center

A

B

C

E

circumference diameter

circumference 2 radius

3.14

3

2area r

arc

(watch the entire video here)

Page 119: GMAT Geometry - everything you need to know

Practice Question

A) 9

B) 12

C) 15

D) 18

E) 36

If is the center, 45 , and 6,then the area of the circle isO OBC BC

C

B

O

Note: Figure not drawn to scale

Page 120: GMAT Geometry - everything you need to know

Practice Question

A) 9

B) 12

C) 15

D) 18

E) 36

If is the center, 45 , and 6,then the area of the circle isO OBC BC

CO

Note: Figure not drawn to scale

45

4590

B

With similar triangles, the ratio of any pair of corresponding

sides is the same

6

2area r

2

area

36

2

18

6

2

r

12

6

2

6 r

r

(watch the entire video here)

Page 122: GMAT Geometry - everything you need to know

Pieces of Pi

C

E

1of circumference

4

90of circumference

360

CE

90

(watch the entire video here)

Page 123: GMAT Geometry - everything you need to know

Pieces of Pi

119

C

E

119of circumference

360CE

(watch the entire video here)

Page 124: GMAT Geometry - everything you need to know

Pieces of Pi

x

C

E

of circumference360

2360

CEx

xr

arc length 2360

xr

(watch the entire video here)

Page 125: GMAT Geometry - everything you need to know

Pieces of Pi

O

C

E 2

of area circ of sect le's area3

r60

o

360

Ox

x

C

r

E

?

(watch the entire video here)

Page 126: GMAT Geometry - everything you need to know

Pieces of Pi

x

C

E 2

of area circ of sect le's area3

r60

o

360

Ox

x

C

r

E

O

2sector area360

xr

360

x

(watch the entire video here)

Page 127: GMAT Geometry - everything you need to know

Pieces of Pi

O

160

6

(watch the entire video here)

Page 128: GMAT Geometry - everything you need to know

Pieces of Pi

O

160

2area360

xr

26area360

436

9

16

160

6

(watch the entire video here)

Page 129: GMAT Geometry - everything you need to know

Pieces of Pi

x

C

E

2360

xCE r

x

C

EO

2area360

xr

(watch the entire video here)

Page 130: GMAT Geometry - everything you need to know

Practice Question

20A)

3

25B)

3

25C)

2

40D)

3

50E)

3

C

B

O

Note: Figure not drawn to scale

O is the center of the circle with radius 30. If x – w=20, what is the length of arc CDE ?

A

E

Dw

xy

Page 131: GMAT Geometry - everything you need to know

20A)

3

25B)

3

25C)

2

40D)

3

50E)

3

C

B

O

Note: Figure not drawn to scale

O is the center of the circle with radius 30. If x – w=20, what is the length of arc CDE ?

A

E

D

x

arc length 2360

yr

y

30

20x w

180x w

2 160

80

w

w

80 80

arc length 2360

260

9

8

4

3

00

0

3

Practice Question (watch the entire video here)

Page 132: GMAT Geometry - everything you need to know

Circle Properties (watch the entire video here)

Page 133: GMAT Geometry - everything you need to know

Circle Properties

A

B

x

“x is an inscribed angle holding/containing chord AB ”

“x is an inscribed angle holding/containing arc AB ”

(watch the entire video here)

Page 134: GMAT Geometry - everything you need to know

Circle Properties

A

B

x

x

Inscribed angles holding the same chord/arc are equal

x

(watch the entire video here)

Page 135: GMAT Geometry - everything you need to know

Circle Properties

A

B

x

C

D

x

Inscribed angles holding chords/arcs of equal length are equal

(watch the entire video here)

Page 136: GMAT Geometry - everything you need to know

Circle Properties

An inscribed angle holding the diameter is a right angle

(watch the entire video here)

Page 137: GMAT Geometry - everything you need to know

Circle Properties

A

B

x

O

“Angle AOB is a central angle holding chord AB”

2x

A central angle is twice as large as an inscribed angle holding the same chord/arc

(watch the entire video here)

Page 138: GMAT Geometry - everything you need to know

Circle Properties

The line from the center to the point of tangency is

perpendicular to the tangent line

“line l is tangent to the circle”

(watch the entire video here)

Page 139: GMAT Geometry - everything you need to know

Circle Properties

**

*

*

x

2x

(watch the entire video here)

Page 140: GMAT Geometry - everything you need to know

Practice Question

Note: Figure not drawn to scale

C

x

20

D

O

B

A

A) 40

B) 50

C) 60

D) 70

E) 80

If is the center and , then O AB CD x

E

Page 141: GMAT Geometry - everything you need to know

Practice Question

Note: Figure not drawn to scale

C

xD

O

B

A

A) 40

B) 50

C) 60

D) 70

E) 80

90

If is the center and , then O AB CD x

A10

2090

90

80

80

E

(watch the entire video here)

Page 142: GMAT Geometry - everything you need to know

Volume & Surface Area (watch the entire video here)

Page 143: GMAT Geometry - everything you need to know

Volume & Surface Area

1 ft1 ft

1 ft31 ft

2 ft3 ft

5 ft

Volume length width height

3

Volume 2 3 5

30 ft

Volume

(watch the entire video here)

Page 144: GMAT Geometry - everything you need to know

Volume & Surface Area

r

height h

2Volume r h

3

2Volume r h

10

2

3Vo 1lume

90

0

Volume

(watch the entire video here)

Page 145: GMAT Geometry - everything you need to know

Volume & Surface Area

Surface Area

face

• 6 faces

• 12 edges

• 8 vertices

(watch the entire video here)

Page 146: GMAT Geometry - everything you need to know

Volume & Surface Area

Surface Area

• 6 faces

• 12 edges

• 8 vertices

edge

edge

edge

edge

(watch the entire video here)

Page 147: GMAT Geometry - everything you need to know

Volume & Surface Area

Surface Area

• 6 faces

• 12 edges

• 8 vertices

vertex

vertex

vertex

vertex

vertex

(watch the entire video here)

Page 148: GMAT Geometry - everything you need to know

Volume & Surface Area

Surface Area

8 cm

4 cm

5 cm

2

surface area 40 40 32 32 20 20

184 cm

(watch the entire video here)

Page 149: GMAT Geometry - everything you need to know

Volume & Surface Area

Surface Area

2area r 2area r

h

2 r

area 2

2

r h

rh

2 2

2

total area 2

2 2

2

r r rh

r rh

r r h

r

h

(watch the entire video here)

Page 150: GMAT Geometry - everything you need to know

Volume & Surface Area

length

volume length width height

width

height

r

2volume r h

2 2

2

surface area 2

2 2

2

r r rh

r rh

r r h

surface area sum of areas of all 6 sides

h

(watch the entire video here)

Page 151: GMAT Geometry - everything you need to know

Units of Measurement (watch the entire video here)

Page 152: GMAT Geometry - everything you need to know

Units of Measurement

• Metric: kilometers, kilograms, liters, etc.

• English: miles, pounds, gallons, etc.

What is the perimeter of this triangle?

12

13

(watch the entire video here)

Page 153: GMAT Geometry - everything you need to know

Units of Measurement

• If conversion is required, relationship will be given

- e.g., (1 kilometer = 1000 meters)

- e.g., (1 mile = 5280 feet)

• Note: Relationships not given for units of time

- e.g., (1 hour = 60 minutes)

Conversions

- e.g., (1 day = 24 hours)

(watch the entire video here)

Page 154: GMAT Geometry - everything you need to know

Geometry Data Sufficiency Questions (watch the entire video here)

Page 155: GMAT Geometry - everything you need to know

Geometry Data Sufficiency Questions

A

B

Cx

• Do not estimate lengths and angles

(watch the entire video here)

Page 156: GMAT Geometry - everything you need to know

Geometry Data Sufficiency Questions

1) 30x

2) AD DC

What is the length of AD?

B

C

D

(watch the entire video here)

Page 157: GMAT Geometry - everything you need to know

Geometry Data Sufficiency Questions

1) 30x

2) AD DC

What is the length of AD?

A

B

C

D

x

• To find one length requires at least one other length

(watch the entire video here)

Page 158: GMAT Geometry - everything you need to know

Geometry Data Sufficiency Questions

1) 30x

2) AD DC

What is the length of AD?

INSUFFICIENT

A

B

C

D

INSUFFICIENT

1&2) 30 &x AD DC

30

INSUFFICIENT

E

(watch the entire video here)

Page 159: GMAT Geometry - everything you need to know

Geometry Data Sufficiency Questions

1) 10AC

2) 30x

If , what is the length of ?AE EC AB

A

B E

xC

D

(watch the entire video here)

Page 160: GMAT Geometry - everything you need to know

Geometry Data Sufficiency Questions

1) 10AC

2) 30x

If , what is the length of ?AE EC AB

A

B E

xC

D

• Sketch figure and add information

(watch the entire video here)

Page 161: GMAT Geometry - everything you need to know

Geometry Data Sufficiency Questions

1) 10AC

2) 30x

If , what is the length of ?AE EC AB

A

B E

x

• Sketch figure and add information

C

D

x

10

(watch the entire video here)

Page 162: GMAT Geometry - everything you need to know

Geometry Data Sufficiency Questions

1) 10AC

2) 30x

If , what is the length of ?AE EC AB

A

B E

x

• Sketch figure and add information

C

D

x

10

• Mentally grab and move points and lines

(watch the entire video here)

Page 163: GMAT Geometry - everything you need to know

Geometry Data Sufficiency Questions

1) 10AC

2) 30x

If , what is the length of ?AE EC AB

A

B E

x

• Sketch figure and add information

C

D

• Mentally grab and move points and lines

10

x

(watch the entire video here)

Page 164: GMAT Geometry - everything you need to know

Geometry Data Sufficiency Questions

1) 10AC

2) 30x

If , what is the length of ?AE EC AB

A

B E

x

• Sketch figure and add information

C

D

• Mentally grab and move points and lines

10

x

(watch the entire video here)

Page 165: GMAT Geometry - everything you need to know

Geometry Data Sufficiency Questions

1) 10AC

2) 30x

If , what is the length of ?AE EC AB

A

B E

• Sketch figure and add information

C

D

• Mentally grab and move points and lines

INSUFFICIENT

INSUFFICIENT

30 30

• To find one length requires at least one other length

(watch the entire video here)

Page 166: GMAT Geometry - everything you need to know

Geometry Data Sufficiency Questions

1) 10AC

2) 30x

If , what is the length of ?AE EC AB

A

B E

C

D

10

30 30

INSUFFICIENT

INSUFFICIENT

1 & 2) 10 and 30AC x SUFFICIENT

C

(watch the entire video here)

Page 167: GMAT Geometry - everything you need to know

Geometry Data Sufficiency Questions

• Do not estimate lengths and angles

• To find one length, requires at least one other length

• Sketch diagram and add information

• Mentally grab and move points and lines

(watch the entire video here)

Page 168: GMAT Geometry - everything you need to know

Geometry Strategies – Part II (watch the entire video here)

Page 169: GMAT Geometry - everything you need to know

• Redraw figures

• Add all given information

• Add any information that can be deduced

• Add/extend lines

• Assign variables and use algebra

• Problem solving questions drawn to scale:

• Circle:

• Break areas/volumes into manageable pieces

• Two or more triangles and length required

• Right triangle:

- use Pythagorean Theorem to relate sides

- watch for Pythagorean Triples and special triangles

- beware of circle properties (inscribed/central angles, tangent lines)

- look for isosceles triangles

- estimate to confirm calculations and guide guesses

- look for similar triangles

Geometry Strategies – Part II (watch the entire video here)

Page 170: GMAT Geometry - everything you need to know

Practice Question

1 2Are lines l1 and l2 parallel?

2) b da

bc

d

e

1) 180e b

A) Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient

B) Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient

C) BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient

D) EACH statement ALONE is sufficient

E) Statements (1) and (2) TOGETHER are NOT sufficient

Page 171: GMAT Geometry - everything you need to know

Practice Question

2) b d

1) 180e b

1 2

a

bc

d

e

180

1 2

SUFFICIENT

SUFFICIENT

D

Are lines l1 and l2 parallel?

(watch the entire video here)

Page 172: GMAT Geometry - everything you need to know

Practice Question

Note: Figure not drawn to scale A) 1

4B)

3

3C)

2

5D)

3

5E)

2

60

1x 4 3x

What is the value of x ?

Page 173: GMAT Geometry - everything you need to know

Practice Question

Note: Figure not drawn to scale A) 1

4B)

3

3C)

2

5D)

3

5E)

2

30

601

2

3

60

1x 4 3x

What is the value of x ?

30

With similar triangles, the ratio of any pair of corresponding

sides is the same

1 4 3

1 2

2 1 1 4 3

2 2 4 3

2 2 3

5 2

5

2

x x

x x

x x

x

x

x

(watch the entire video here)

Page 174: GMAT Geometry - everything you need to know

Practice Question

Note: Figure not drawn to scale

If is tangent to the circle with center , then AC O DBC

D

O

B CA

40

A) 50°

B) 55°

C) 60°

D) 65°

E) 70°

Page 175: GMAT Geometry - everything you need to know

Practice Question

Note: Figure not drawn to scale

If is tangent to the circle with center , then AC O DBC

D

O

B CA

40

A) 50°

B) 55°

C) 60°

D) 65°

E) 70°

50

130

25

25

65

(watch the entire video here)

Page 176: GMAT Geometry - everything you need to know

Practice Question

B

A C D

2) AC CD

1) 5BC

If 12, does 90 ?AC ACB

A) Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient

B) Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient

C) BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient

D) EACH statement ALONE is sufficient

E) Statements (1) and (2) TOGETHER are NOT sufficient

Page 177: GMAT Geometry - everything you need to know

Practice Question

2) AC CD

1) 5BC INSUFFICIENT

B

If 12, does 90 ?AC ACB

A C D12

INSUFFICIENT

1 & 2)

12

5

INSUFFICIENT

E

(watch the entire video here)

Page 178: GMAT Geometry - everything you need to know

Practice Question

What is the area of triangle ?ABC

60

5

12

Note: Figure not drawn to scale A) 15

B) 15 3

5 119C)

2

D) 32.5

E) 36

A

BC

Page 179: GMAT Geometry - everything you need to know

Practice Question

What is the area of triangle ?ABC

60

Note: Figure not drawn to scale A) 15

B) 15 3

5 119C)

2

D) 32.5

E) 36

enlargement factor: 6

12

3 6 36h

6 3

5

A

BC

base heightarea

2

5 6 3area

2

30 3

2

15 3

(watch the entire video here)

Page 180: GMAT Geometry - everything you need to know

Practice Question

If is a parallelogram, then what is its perimeter?ABCD

Note: Figure not drawn to scale

A B

CD

3 3x y

4 2 2y x

6x y 2 6 13x y

A) 22

B) 24

C) 26

D) 28

E) 30

Page 181: GMAT Geometry - everything you need to know

Practice Question

If is a parallelogram, then what is its perimeter?ABCD

Note: Figure not drawn to scale A) 22

B) 24

C) 26

D) 28

E) 30

perimeter 3 3 2 6 13 4 2 2

1

6

4 4 18

4 18

4 18

22

x y x y y x x y

x

x

y

y

A B

CD

6 2 6 13

5 7

x y x y

x y

6x y 2 6 13x y 3 3 4 2 2

5

1

5 5

x y y x

x

x

y

y

4 2 2y x

3 3x y

(watch the entire video here)

Page 182: GMAT Geometry - everything you need to know

Practice Question

What is the value of ?x

Note: Figure not drawn to scale

155 3x

6 30x

4 70x

A) 5

B) 7

C) 15

D) 21

E) 25

Page 183: GMAT Geometry - everything you need to know

Practice Question

What is the value of ?x

Note: Figure not drawn to scale

155 3x

6 30x

4 70x

A) 5

B) 7

C) 15

D) 21

E) 25

180 4 70x

180 155 3x

6 30x

180 4 70 180 155 3 6 30 180

110 4 25 3 6 30 180

105 5 180

5 75

15

x x x

x x x

x

x

x

(watch the entire video here)

Page 184: GMAT Geometry - everything you need to know

Practice Question

K is the surface area of cylinder A. If the radius of cylinder B is twice the radius of cylinder A, and the height of cylinder B is twice that of cylinder A, what is the surface area of cylinder B?

A) 2K

B) 3K

C) 4K

D) 6K

E) 8K

Page 185: GMAT Geometry - everything you need to know

Practice Question

K is the surface area of cylinder A. If the radius of cylinder B is twice the radius of cylinder A, and the height of cylinder B is twice that of cylinder A, what is the surface area of cylinder B?

A) 2K

B) 3K

C) 4K

D) 6K

E) 8K

2surface area 2 2r rh 1

1

22 2

2 2

1 1 1

4

2

2

2surface area 2 2r rh

2

2 2

8 8

1

2 2 2

6

A

B

K

4K

(watch the entire video here)

Page 186: GMAT Geometry - everything you need to know

Practice Question

Note: Figure not drawn to scale

2) AC AB

1) 8CB

C

B

A

x

If the circle has radius 4, is 80?x

Page 187: GMAT Geometry - everything you need to know

Practice Question

Note: Figure not drawn to scale

2) AC AB

1) 8CB

C

B

A

x

If the circle has radius 4, is 80?x

SUFFICIENT

INSUFFICIENT

A

(watch the entire video here)

Page 188: GMAT Geometry - everything you need to know

Practice Question

2) BE EA

1) 30BCE

If ABCD is a rectangle, is the area of ∆EBC greater than the area of ∆AEC ?

C B

AD

E

Page 189: GMAT Geometry - everything you need to know

Practice Question

2) BE EA

1) 30BCE

C B

AD

E

If ABCD is a rectangle, is the area of ∆EBC greater than the area of ∆AEC ?

B E A

DC

harea2

bh

Which triangle has the longest base? INSUFFICIENT

SUFFICIENT

B

(watch the entire video here)

Page 190: GMAT Geometry - everything you need to know

Practice Question

Note: Figure not drawn to scale

21) 14 48 0y y

A C

B

55

y

hat is the area of ?W ABC

22) 16 60 0y y

A) Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient

B) Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient

C) BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient

D) EACH statement ALONE is sufficient

E) Statements (1) and (2) TOGETHER are NOT sufficient

Page 191: GMAT Geometry - everything you need to know

Practice Question

Note: Figure not drawn to scale

21) 14 48 0y y

A C

B

55

y

hat is the area of ?W ABC

22) 16 60 0y y

21) 14 48 0

6 8 0

6, 8

y y

y y

y

area 12

area 12

SUFFICIENT

h

22) 16 60 0

6 10 0

6, 10

y y

y y

y

area 12

The sum of the lengths of any two sides of a

triangle must be greater than the third side.

5 5 10

SUFFICIENT

D

(watch the entire video here)

Page 192: GMAT Geometry - everything you need to know

Practice Question

Note: Figure not drawn to scale

A

BD

C

E F

If bisects , and bisects , then BD CBE DE BEF w

w

50

A) 25

B) 35

C) 50

D) 55

E) 65

Page 193: GMAT Geometry - everything you need to know

Practice Question

Note: Figure not drawn to scale

A

BD

C

E F

If bisects , and bisects , then BD CBE DE BEF w

w

50

xx

yy 180 2y

180 2x

50 180 2 180 2 180

410 2 2 180

230 2 2

23

5

0

11

2

x y

x y

x y

x

x y

y

A) 25

B) 35

C) 50

D) 55

E) 65

180

180

180 x

w x y

w x

y

y

w

11180

65

5

(watch the entire video here)

Page 194: GMAT Geometry - everything you need to know

Practice Question

Note: Figure not drawn to scale

If is a rectangle, then what is the length of ?ABCD EC

A) 7.8

B) 8

C) 8.4

D) 9

E) 9.6

A

B

D

C

E

12

16

Page 195: GMAT Geometry - everything you need to know

Practice Question

Note: Figure not drawn to scale

If is a rectangle, then what is the length of ?ABCD EC

A) 7.8

B) 8

C) 8.4

D) 9

E) 9.6

A

B

D

C

E

B

C

DE

D C

B

E

12

16

16

16

121216

20

area2

bh

12 16area

9

2

6

h

area2

bh

20

2

96 10

.6

9

9

6h

h

h

EC

(watch the entire video here)

Page 196: GMAT Geometry - everything you need to know

Practice Question

If the both circles have radius 6, and O and P are their centers, what is the area of the shaded region?

A) 24 18 3

B) 24 12 3

C) 18

D) 36 24 3

E) 18 12 3

PO

Page 197: GMAT Geometry - everything you need to know

Practice Question

If the both circles have radius 6, and O and P are their centers, what is the area of the shaded region?

A) 24 18 3

B) 24 12 3

C) 18

D) 36 24 3

E) 18 12 3

cab

2 660

6360

6

6

6

a b

d e

b c

d f

2sector area360

xr

O

e

P

fd

24

24

24 24

24

24 1

9 3 3

8

9

3

b d

b d b d

a b d e b c d f

a b c d e f

a b c d e f

a b c d e f

a b c d e f

b66

6

2

3 sidearea

4

23b 3

69

4

b d a b c d e f

(watch the entire video here)

Page 198: GMAT Geometry - everything you need to know

GMAT Geometry - Everything you need to know

For additional practice questions, see the bottom of our Geometry module

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Page 199: GMAT Geometry - everything you need to know

GMAT Geometry - Everything you need to know

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