gmat geometry - everything you need to know
TRANSCRIPT
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
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.
GMAT Geometry - Everything you need to know
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Lines and Angles (watch the entire video here)
Lines and Angles
l
line: a straight path that extends without end in both directions
(watch the entire video here)
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)
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)
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)
Lines and Angles
90
right angle: angle of 90 degrees
P
PQ is perpendicular to AB
BA Q
(watch the entire video here)
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)
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)
Lines and Angles
w 50
yx
(watch the entire video here)
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)
Lines and Angles
1
2
If two lines do not intersect, they are parallel
1 2
(watch the entire video here)
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)
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)
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
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)
Triangles – Part I (watch the entire video here)
Triangles – Part I
A
B Cw x
y180w x y
Angles in a triangle add to 180°
(watch the entire video here)
Triangles – Part I
A
B C21
44180w x y
Angles in a triangle add to 180°
w
(watch the entire video here)
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)
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)
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)
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)
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)
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)
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
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
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
(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
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
Assumptions and Estimation (watch the entire video here)
Assumptions and Estimation
120
• Lines that appear straight can be assumed to be straight
(watch the entire video here)
Assumptions and Estimation
120
60
• Lines that appear straight can be assumed to be straight
(watch the entire video here)
• Do not make assumptions about angle measurements
x
Assumptions and Estimation (watch the entire video here)
y
• y +x =180
• Both angles are greater than zero degrees
x
Assumptions and Estimation
(watch the entire video here)
• Do not make assumptions about parallelism
1
2
1 2
Assumptions and Estimation (watch the entire video here)
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)
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)
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)
Geometry Strategies – Part I (watch the entire video here)
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)
Triangles – Part II (watch the entire video here)
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)
Triangles – Part II
38
(watch the entire video here)
Triangles – Part II
38
38
104
(watch the entire video here)
Triangles – Part II
38
38
104
40
(watch the entire video here)
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)
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)
Triangles – Part II
A
B
C
Equilateral triangle
• 3 equal sides, 3 equal angles
60 60
60
(watch the entire video here)
Triangles – Part II
A
B C
10
48
Area
- ft 2
- cm 2
- m 2
(watch the entire video here)
Triangles – Part II
A
B C
base heightArea
2
10
48
Area
1Area base height
2
(watch the entire video here)
Triangles – Part II
A
B C
base heightArea
2
10Area
15
3
2
10
34
8
altitude height
Area
(watch the entire video here)
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)
Triangles – Part II
A
B
C60 60
60
2
3 sideArea
4
(watch the entire video here)
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)
Triangles – Part II
60 60
60
The altitudes of isosceles triangles and equilateral triangles bisect the base.
(watch the entire video here)
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)
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
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)
Right Triangles (watch the entire video here)
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)
Right Triangles
8
6
x
(watch the entire video here)
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)
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)
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)
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)
Right Triangles
8x 17
15
• 8-15-17
2 2 215 17x
2 2 2a b c
(watch the entire video here)
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)
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)
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)
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)
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)
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
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)
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
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
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
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)
Special Right Triangles
1230
x
y
(watch the entire video here)
Special Right Triangles
1230
x
y 30
601
2
3
60
enlargement factor: 6
(watch the entire video here)
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)
Special Right Triangles
5 2
x
5 2
(watch the entire video here)
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)
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)
Special Right Triangles
45
12
451
30
601
2
3
(watch the entire video here)
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
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)
Similar Triangles (watch the entire video here)
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)
Similar Triangles
**
x
5 7
9
6
(watch the entire video here)
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)
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)
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
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)
Quadrilaterals (watch the entire video here)
Quadrilaterals
Angles in a quadrilateral add to 360°
A
D C
w
x
y360w x y z
B
z
(watch the entire video here)
Quadrilaterals
square
rectangle
trapezoid
parallelogram
rhombus
(watch the entire video here)
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)
Quadrilaterals
trapezoid
2 sides parallel
(watch the entire video here)
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)
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)
Quadrilaterals
rhombus
1 2diagonal diagonalarea
2
4
7
area2
28
2
14
4 7
(watch the entire video here)
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)
Polygons (watch the entire video here)
Polygons
Polygon: Closed figure formed by 3 or more line segments
(watch the entire video here)
Polygons
“polygon” “convex polygon” (all interior angles less than 180°)
(watch the entire video here)
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)
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)
Polygons
Regular polygon: equal sides and equal angles
regular pentagon
(watch the entire video here)
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)
Circles (watch the entire video here)
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)
Circles
circumference 2 radius
2 r
Circumference 3.14
3
22
7
circumference diameter
d
(watch the entire video here)
Circles
circumference 2 r
Circumference
circumference 2
16 feet
16 3
48 f
8
eet
8 ft
(watch the entire video here)
Circles
Area
2area r
2
2
area
6
8
4 ft
8 ft
(watch the entire video here)
Circles
center
A
B
C
E
circumference diameter
circumference 2 radius
3.14
3
2area r
arc
(watch the entire video here)
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
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)
Pieces of Pi (watch the entire video here)
Pieces of Pi
C
E
1of circumference
4
90of circumference
360
CE
90
(watch the entire video here)
Pieces of Pi
119
C
E
119of circumference
360CE
(watch the entire video here)
Pieces of Pi
x
C
E
of circumference360
2360
CEx
xr
arc length 2360
xr
(watch the entire video here)
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)
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)
Pieces of Pi
O
160
6
(watch the entire video here)
Pieces of Pi
O
160
2area360
xr
26area360
436
9
16
160
6
(watch the entire video here)
Pieces of Pi
x
C
E
2360
xCE r
x
C
EO
2area360
xr
(watch the entire video here)
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
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)
Circle Properties (watch the entire video here)
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)
Circle Properties
A
B
x
x
Inscribed angles holding the same chord/arc are equal
x
(watch the entire video here)
Circle Properties
A
B
x
C
D
x
Inscribed angles holding chords/arcs of equal length are equal
(watch the entire video here)
Circle Properties
An inscribed angle holding the diameter is a right angle
(watch the entire video here)
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)
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)
Circle Properties
**
*
*
x
2x
(watch the entire video here)
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
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)
Volume & Surface Area (watch the entire video here)
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)
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)
Volume & Surface Area
Surface Area
face
• 6 faces
• 12 edges
• 8 vertices
(watch the entire video here)
Volume & Surface Area
Surface Area
• 6 faces
• 12 edges
• 8 vertices
edge
edge
edge
edge
(watch the entire video here)
Volume & Surface Area
Surface Area
• 6 faces
• 12 edges
• 8 vertices
vertex
vertex
vertex
vertex
vertex
(watch the entire video here)
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)
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)
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)
Units of Measurement (watch the entire video here)
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)
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)
Geometry Data Sufficiency Questions (watch the entire video here)
Geometry Data Sufficiency Questions
A
B
Cx
• Do not estimate lengths and angles
(watch the entire video here)
Geometry Data Sufficiency Questions
1) 30x
2) AD DC
What is the length of AD?
B
C
D
(watch the entire video here)
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)
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)
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)
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)
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)
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)
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)
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)
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)
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)
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)
Geometry Strategies – Part II (watch the entire video here)
• 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)
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
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)
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 ?
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)
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°
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)
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
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)
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
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)
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
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)
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
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)
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
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)
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
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)
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
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)
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
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)
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
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)
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
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)
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
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)
GMAT Geometry - Everything you need to know
For additional practice questions, see the bottom of our Geometry module
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GMAT Geometry - Everything you need to know
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