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Page 1: Geometry Chapter 3 Notes - Canyon Crest Academy …teachers.sduhsd.net/chayden/documents/Chapter3Notes08.pdf · Geometry Chapter 3 Notes Notes #13: Section 3.1 and Algebra Review

­ 1 ­ Geometry Chapter 3 Notes

Notes #13: Section 3.1 and Algebra Review

A. Definitions:

Parallel Lines:

Draw:

Example:

Transversal: a line that intersects two or more coplanar lines in different points

Draw:

Example:

Parallel Planes:

Draw:

Example:

Practice:

1.) Name a plane parallel to ABGH.

2.) Name three lines parallel to CF suur

3.) Classify the planes as intersecting or parallel: ADEH and BCFG

4.) Draw and label the figure described: AB suur

and XY suur

are coplanar and parallel. h is a transversal that intersects them at points C and Z, respectively.

B. Special Angles: The angles formed by lines and their transversals are special: Alternate Interior Angles: ( ) Same­side Interior Angles: ( )

Page 2: Geometry Chapter 3 Notes - Canyon Crest Academy …teachers.sduhsd.net/chayden/documents/Chapter3Notes08.pdf · Geometry Chapter 3 Notes Notes #13: Section 3.1 and Algebra Review

­ 2 ­ Corresponding Angles: ( ) Alternate Exterior Angles: ( )

Same­side Exterior Angles: ( )

Vertical Angles: (reminder) ( )

Practice: Classify each pair of angles as alt. int., s­s int., corr, alt. ext., s­s ext, or vertical. 5.) 1, 5 ∠ ∠ 6.) 2, 8 ∠ ∠

7.) 4, 2 ∠ ∠ 8.) 3, 8 ∠ ∠

9.) 1, 7 ∠ ∠ 10.) 4, 7 ∠ ∠

8 7 6 5 4 3

2 1

C. Identifying Lines and Transversals: Name the two lines and the transversal that form each pair of angles. What type of special angles are they? (Hint: Trace the angles in two different colors – where they overlap is the transversal, the leftovers are the two lines.)

11.) 4, 2 ∠ ∠ lines: ____, _____ transversal: ______ type: _______________

12.) , B BAD ∠ ∠ lines: ____, _____ transversal: ______ type: _______________

13.) , 5 BAD ∠ ∠ lines: ____, _____ transversal: ______ type: _______________

5 4 3

2 1

B

A

C

D E

14.) , 5 BCD ∠ ∠ lines: ____, _____ transversal: ______ type: _______________

Page 3: Geometry Chapter 3 Notes - Canyon Crest Academy …teachers.sduhsd.net/chayden/documents/Chapter3Notes08.pdf · Geometry Chapter 3 Notes Notes #13: Section 3.1 and Algebra Review

­ 3 ­ D. Algebra Practice: Solving Linear Systems by Addition/Subtraction/Elimination

­ Rearrange each equation so that the variable expressions are on the left side of the equals sign and the constant is on the right side of the equal sign (called Standard Form) ­ Multiply whole equations so that one variable expression is equal but has the opposite sign. ­Add the equations together; watch one variable cancel out ­Solve for BOTH variables ­Write your answer as a point ( x, y ) (in alphabetical order)

15.) 2x – 3y = 8 16.) x = ­4y ­ 3 4x + 3y = ­2 3x – 2y = 5

17.) 3x – 5y = ­11 18.) 2x + 3y – 10 = x + y ­ 14 2x – 4y = ­9 x – 2y + 5 = 2x – y + 6

Solve for x and y: 19.)

2x ­ y 70

3x ­ 35 x ­ 15

Page 4: Geometry Chapter 3 Notes - Canyon Crest Academy …teachers.sduhsd.net/chayden/documents/Chapter3Notes08.pdf · Geometry Chapter 3 Notes Notes #13: Section 3.1 and Algebra Review

­ 4 ­ Notes #14: Sections 3.1 and 3.2

A. Relationships formed by parallel lines

Alternate Interior Angles Theorem

If two ________________ lines are cut by a __________, then alternate interior angles are _________________.

(Its converse): If two lines cut by a ________________ form congruent alternate interior angles, then the lines are ________________.

Corresponding Angles Postulate

If two ________________ lines are cut by a __________, then corresponding angles are _________________.

(Its converse): If two lines cut by a ________________ form congruent corresponding angles, then the lines are ________________.

Same­Side Interior Angles Theorem

If two ________________ lines are cut by a __________, then same­side interior angles are _________________.

(Its converse): If two lines cut by a ________________ form supplementary same­side interior angles, then the lines are ________________.

Alternate Exterior Angles Theorem

If two ________________ lines are cut by a __________, then alternate exterior angles are _________________.

(Its converse): If two lines cut by a ________________ form congruent alternate exterior angles, then the lines are ________________.

Same­Side Exterior Angles Theorem

If two ________________ lines are cut by a __________, then same­side exterior angles are _________________.

(Its converse): If two lines cut by a ________________ form supplementary same­side exterior angles, then the lines are ________________.

Page 5: Geometry Chapter 3 Notes - Canyon Crest Academy …teachers.sduhsd.net/chayden/documents/Chapter3Notes08.pdf · Geometry Chapter 3 Notes Notes #13: Section 3.1 and Algebra Review

­ 5 ­ Complete the sentences and solve for x.

1.) The labeled angles are ____________ angles and their measures are ___________ because of the _________________________________________

3x + 10

100

2.) The labeled angles are ____________ angles and their measures are ______________________ because of the _____________________________

120 3x

3.) The labeled angles are ____________ angles and their measures are ___________________ because of the _____________________________

2x + 52

4x ­ 8

4.) The labeled angles are ____________ angles and their measures are ___________________ because of the _____________________________

2x + 21 7x ­ 4

B. Identifying Parallel Lines: Use the given information to name the lines that must be parallel. (Trace angles and look for special pairs of angles and special relationships.)

10

9

8 7 6

5 4 3

2 1

W

S T

U

V

5.) 1 4 ∠ ≅ ∠ Type of angle pair: Relationship:

Parallel lines?:

6.) 1 2 3 180 m m m ∠ + ∠ + ∠ = o

Type of angle pair: Relationship:

Parallel lines?:

7.) 9 2 ∠ ≅ ∠ Type of angle pair: Relationship:

Parallel lines?:

8.) 4 7 ∠ ≅ ∠ Type of angle pair: Relationship:

Parallel lines?:

9.) 2 10 ∠ ≅ ∠ Type of angle pair: Relationship:

Parallel lines?:

Page 6: Geometry Chapter 3 Notes - Canyon Crest Academy …teachers.sduhsd.net/chayden/documents/Chapter3Notes08.pdf · Geometry Chapter 3 Notes Notes #13: Section 3.1 and Algebra Review

­ 6 ­

C. Special Pairs of Angles

Solve for all variables. All measurements are in degrees. (Hint: extend the parallel lines and look for special pairs of angles)

10.)

120

x y

11.)

4x

120

80

2y

12.)

e

d c

b a

27

60

56

13.)

130

2x ­ 5y 2x ­ 3y

110

D. Proofs with Parallel Lines:

14.) Prove the alternate exterior angles theorem:

If a transversal intersects two parallel lines, then alternate exterior angles are congruent.

Given: k l P Prove: 1 3 ∠ ≅ ∠

l

k

3 2

1

Statements Reasons 1.)

2.)

3.) 3 ____ ∠ ≅ ∠

4.)

1.)

2.) Corresponding Angle Postulate

3.)

4.)

Page 7: Geometry Chapter 3 Notes - Canyon Crest Academy …teachers.sduhsd.net/chayden/documents/Chapter3Notes08.pdf · Geometry Chapter 3 Notes Notes #13: Section 3.1 and Algebra Review

­ 7 ­

15.) Prove the converse of the alternate exterior angles theorem:

If two lines and a transversal form alternate exterior angles that are congruent, then the two lines are parallel.

Given: 1 3 ∠ ≅ ∠ Prove: m n P

n

m

3

2 1

Statements Reasons 1.)

2.) 1 _____ ∠ ≅

3.)

4.)

1.)

2.)

3.) Substitution

4.) If two lines and a transversal form ____________ __________________ angles, then the two lines are ________________.

Notes #15: Sections 3.3 and 3.4 A. Parallel and Perpendicular Lines

Prove the converse of the same­side interior angles theorem:

If two lines and a transversal form same­side interior angles that are supplementary, then the two lines are parallel.

Given: 2 ∠ and 3 ∠ are supplementary Prove: m n P

n

m

3

2 1

Statements Reasons 1.)

2.) 2 3 _____ m m ∠ + ∠ =

3.) 2 ____ _____ m m ∠ + ∠ =

4.)

5.) 2 2 m m ∠ = ∠

6.)

7.)

1.)

2.) Definition of __________________ angles

3.)

4.) Substitution

5.)

6.) Subtraction

7.) If two lines and a transversal form ____________ __________________ angles, then the two lines are ________________.

Page 8: Geometry Chapter 3 Notes - Canyon Crest Academy …teachers.sduhsd.net/chayden/documents/Chapter3Notes08.pdf · Geometry Chapter 3 Notes Notes #13: Section 3.1 and Algebra Review

­ 8 ­

If two lines are parallel to the same line, then they are ___________ to each other.

In a plane, if two lines are perpendicular to the same line, then they are _____________ to each other.

In a plane, if a line is perpendicular to one of two parallel lines, then it is also _____________ to the other.

Examples: For #1­3, consider coplanar lines j, k, l, and m. Given each of the following statements, what more, if anything, can you conclude about the lines?

1.) , j k k m P P 2.) , j k l k ⊥ P 3.) , , j k k l l m ⊥ ⊥ P

B. Classifying Triangles Triangles are described based on the lengths of their sides and the measures of their angles

Sides

Scalene Isosceles Equilateral

Page 9: Geometry Chapter 3 Notes - Canyon Crest Academy …teachers.sduhsd.net/chayden/documents/Chapter3Notes08.pdf · Geometry Chapter 3 Notes Notes #13: Section 3.1 and Algebra Review

­ 9 ­ Angles Acute Obtuse Right

Equiangular

Examples: For #5­7, classify each triangle (drawn to scale) by its angles and sides. 5.) 6.) 7.)

For #8­10, draw a triangle, if possible, to fit each description. 8.) obtuse scalene 9.) acute isosceles 10.) right equilateral

11.) The perimeter of ∆ABC is 32m. AB = 4x – 2, BC = 3x + 1, AC = 2x + 6. Write an equation and solve for x. Then, classify the triangle as scalene, isosceles, or equilateral. (Hint: draw a picture first and label what you know)

C. The angles of a triangle:

** The sum of the interior angles of a triangle is always ______**

Page 10: Geometry Chapter 3 Notes - Canyon Crest Academy …teachers.sduhsd.net/chayden/documents/Chapter3Notes08.pdf · Geometry Chapter 3 Notes Notes #13: Section 3.1 and Algebra Review

­ 10 ­

13.) Find the missing values and classify LMN V : 12.)

3

2

1

1 2 3 _____ m m m ∠ + ∠ + ∠ = x

4x + 11

2x + 8

M

L N

LMN V is __________ and __________

____ ____ ____ ____

x m L m M m N

= ∠ = ∠ = ∠ =

14.) Find the values of each variable and the measure of each angle. Then classify each triangle by its angles. (All measurements shown are in degrees)

134

61 w x

y

z D

C

B A ____ ____ ____ ____

w x y z

= = = =

is _________ is _________ is _________

ABC ABD DBC

V V V

** The measure of an exterior angle of a triangle equals the sum of the measures of the two _________________ __________________ angles.**

Explore:

85

40

1 2

3 4

5 6

7

Diagram for #15

15.) Complete:

1 2 _____ 2 7 _____ 7 3 _____ 4 3 5 6 _____ 2 3 7 _____

m m m m m m m m m m m m m

∠ + ∠ = ∠ + ∠ = ∠ + ∠ = ∠ + ∠ + ∠ + ∠ = ∠ + ∠ + ∠ =

Page 11: Geometry Chapter 3 Notes - Canyon Crest Academy …teachers.sduhsd.net/chayden/documents/Chapter3Notes08.pdf · Geometry Chapter 3 Notes Notes #13: Section 3.1 and Algebra Review

­ 11 ­

16.) Solve for x and y:

y

95

50 x

17.) 2 103 , 3 156 , 1 _____ m m m ∠ = ∠ = ∠ = o o

3

2

1

Notes #16: Section 3.5 and Algebra Review

A. Polygons: ( _________ sided figures)

Convex Polygon Concave Polygon

Explore: Triangle ____ sides

Sum of Interior Angles = ______ Sum of Exterior Angles = ______

Quadrilateral____ sides

Sum of Interior Angles = ______ Sum of Exterior Angles = ______

Pentagon ____ sides

Sum of Interior Angles = ______ Sum of Exterior Angles = ______

Hexagon ____ sides

Sum of Interior Angles = ______ Sum of Exterior Angles = ______

Other Common Polygons: Octagon: ______ sides Nonagon: ______ sides Decagon: ________ sides Dodecagon: ________ sides

18­gon: ______ sides 20­gon: ______ sides n­gon: ______ sides

Page 12: Geometry Chapter 3 Notes - Canyon Crest Academy …teachers.sduhsd.net/chayden/documents/Chapter3Notes08.pdf · Geometry Chapter 3 Notes Notes #13: Section 3.1 and Algebra Review

­ 12 ­ Patterns for polygonal angle sums:

Sum of Interior Angles Sum of Exterior Angles

each interior angle + each exterior angle = ___________

Find the sum of the measures of the angles of each polygon: (interior angles)

1.) decagon 2.) octagon 3.) 22­gon

Find the missing angle measures: (all measures shown are in degrees) 4.)

130

a

114 28

5.) b 131

107

160

123

85

B. Regular Polygons (where n is the number of sides in the polygon)

Regular Polygons: all sides ________________

all angles ________________

Interior Angles

Sum of Interior Angles:

OR

Each Interior Angle:

Exterior Angles

Sum of Exterior Angles:

Each Exterior Angle:

Extra Trick:

(each interior angle) + (each exterior angle) = ________

Page 13: Geometry Chapter 3 Notes - Canyon Crest Academy …teachers.sduhsd.net/chayden/documents/Chapter3Notes08.pdf · Geometry Chapter 3 Notes Notes #13: Section 3.1 and Algebra Review

­ 13 ­ Complete the chart using these relationships. (Pictures may help!)

6. 7. 8. 9. 10. 11. # of sides (n) 6 8 Sum of Exterior Angles Each Exterior Angle 72˚ Each Interior Angle 90˚ Sum of Interior Angles 900˚ 2880˚

6.) 7.) 8.)

9.) 10.) 11.)

D. Word Problems: Define two variables and write two equations to solve.

12.) The sum of two numbers is 18 and their difference is 6. Find each of the numbers.

13.) The sum of two numbers is one more than twice the smaller number. Their difference is seven less than twice the larger number. Find the numbers.

Page 14: Geometry Chapter 3 Notes - Canyon Crest Academy …teachers.sduhsd.net/chayden/documents/Chapter3Notes08.pdf · Geometry Chapter 3 Notes Notes #13: Section 3.1 and Algebra Review

­ 14 ­

D. Algebra Practice: Solving linear systems with fractions and/or decimals.

To clear decimals: ­ multiply both sides of the equation by a multiple of 10; scoot the decimal over

To clear fractions: ­ multiply both sides of the equation by the common denominator; cross cancel

14.) 0.2 0.5 1.4 1 1 1 2 3 3

m n

m n

− = −

+ = − 15.)

0.2 1.2 8.8 1 1 1 4 6 6

m n

m n

+ =

− =

Notes #17: Section 3.6

A. Slope:

Slope is used to describe the ________________ and _________________ of lines.

Sketch a line with: a) positive slope b) negative slope c) zero slope d) undefined slope

Page 15: Geometry Chapter 3 Notes - Canyon Crest Academy …teachers.sduhsd.net/chayden/documents/Chapter3Notes08.pdf · Geometry Chapter 3 Notes Notes #13: Section 3.1 and Algebra Review

­ 15 ­ A line is shown. Use two marked points and count “rise over run” to find the slope of the line. 1.) 2.) 3.)

Slope = Slope = Slope =

Without using a graph and given two points: ( ) 1 1 , x y and ( ) 2 2 , x y

Slope = m = 2 1

2 1

y y x x

− −

0 0

0

n

n undefined

=

=

For #4­5, find the slope of the line passing through the two given points:

4.) (­4, 1), (3, 2) 5.) (6, ­3) and (2, ­1) 6.) A line with slope

7 3 passes through the

points (1, 2) and (­2, y). Find y.

B. Graphing Lines

There are many ways to graph a line. You need to know how to graph a line: (i) given a point and a slope, (ii) by finding the x­intercept and y­intercept, and (iii) by finding the y­intercept and the slope of the line.

Page 16: Geometry Chapter 3 Notes - Canyon Crest Academy …teachers.sduhsd.net/chayden/documents/Chapter3Notes08.pdf · Geometry Chapter 3 Notes Notes #13: Section 3.1 and Algebra Review

­ 16 ­ (i) Graphing lines using a point and a slope A point P on a line and the slope of the line are given. Sketch the line and find the coordinates of two other points on the line

7.) 8.) 9.)

P (­2, 1); slope = 4 5

1 st point:

2 nd point:

P (0, ­3); slope = ­2

1 st point:

2 nd point:

P (2, 0); slope = ­ 2 3

1 st point:

2 nd point:

(ii). Graphing Lines using the x­ and y­ intercepts. The intercepts are the point(s) where a line intersects the axes of the coordinate plane. ­ Find the x and y intercepts (by setting the opposite variable to zero) ­ Write these answers as two different points ­ Graph and connect these points to graph the line ­ Label the graphed line with the original equation

Most common error: • Forgetting that the intercepts are two different points and graphing as just one

10.) x + 2y = 4 x­intercept y­intercept (set y = 0) (set x = 0)

x­int: ( , 0) y­int: (0, )

11.) 3x – y = 3

x­int: ( , ) y­int: ( , )

­10 ­9 ­8 ­7 ­6 ­5 ­4 ­3 ­2 ­1 1 2 3 4 5 6 7 8 9 10 x

­10

­9 ­8

­7

­6 ­5

­4

­3 ­2

­1

1 2

3

4 5

6

7

8 9

10 y

Page 17: Geometry Chapter 3 Notes - Canyon Crest Academy …teachers.sduhsd.net/chayden/documents/Chapter3Notes08.pdf · Geometry Chapter 3 Notes Notes #13: Section 3.1 and Algebra Review

­ 17 ­

(iii) Graphing Lines using the slope and y­intercept: ­ Get y alone so the equation is in y = mx + b form (m = _________, b = _________) ­ Graph b first. This point goes on the ____ axis. ­ Use slope and count rise over run to the next point(s). When you have at least three points, then connect the points to make a line. ­ Label your graphed line with the original equation

Most common errors: • Graphing b on the x­axis instead of the y­axis • Graphing the slope in the wrong direction (e.g. forgetting a negative)

12.) 1 5 2

y x = − −

(↑ I’m already in slope­intercept form!)

m = ___ (ß graph me second! Watch the negative!)

b = ___ (ß graph me first! I go on the y­axis!)

13.) x – 2y =2 (↑ Get me in slope­intercept form first)

m = ______

b = ______

14.) x + 3y = ­6 (↑ Get me in slope­intercept form first)

m = ______

b = ______

­10­9 ­8 ­7 ­6 ­5 ­4 ­3 ­2 ­1 1 2 3 4 5 6 7 8 9 10 x

­10

­9 ­8

­7

­6 ­5

­4

­3 ­2

­1

1 2

3

4 5

6

7

8 9

10 y

­10­9 ­8 ­7 ­6 ­5 ­4 ­3 ­2 ­1 1 2 3 4 5 6 7 8 9 10 x

­10

­9 ­8

­7

­6 ­5

­4

­3 ­2

­1

1 2

3

4 5

6

7

8 9

10 y

Graph for #13 AND #14 (be sure to label your lines!)

Page 18: Geometry Chapter 3 Notes - Canyon Crest Academy …teachers.sduhsd.net/chayden/documents/Chapter3Notes08.pdf · Geometry Chapter 3 Notes Notes #13: Section 3.1 and Algebra Review

­ 18 ­ Special Cases: Graphing Horizontal and Vertical Lines

15.) x = 4 (This equation describes the line for which ALL points have an x­ coordinate of 4. There are no restrictions on the value of y).

16.) y = ­2 (This equation describes the line for which ALL points have an y­ coordinate of ­2. There are no restrictions on the value of x).

17) x = 1

Use the pattern you found above to complete these sentences: • Any line in the form x = _____ is a ________________ line because it intersects the ___ _________

• Any line in the form y = _____ is a ________________ line because it intersects the ___ _________

Use this pattern to graph these lines without a table of solutions. 18.) y = 3 19.) x = ­2 20.) y = ­4

Page 19: Geometry Chapter 3 Notes - Canyon Crest Academy …teachers.sduhsd.net/chayden/documents/Chapter3Notes08.pdf · Geometry Chapter 3 Notes Notes #13: Section 3.1 and Algebra Review

­ 19 ­ Notes #18: Writing Linear Equations

A. Converting equations of lines: Lines can be written in either Slope­Intercept form (y = mx + b) or Standard Form (Ax + By = C). You need to know how to convert from one to the other.

Converting to Slope­Intercept Form

Goal: y =mx + b (where m and b are integers or fractions)

• Get y alone • Reduce all fractions

Converting to Standard Form

Goal: Ax + By = C (where A, B, and C are integers and

where A is positive)

• Get x and y terms on the left side and the constant term on the right side of the equation

• Multiply ALL terms by the common denominator to eliminate the fractions

• If necessary, change ALL signs so that the x term is positive

1.) Convert to slope­intercept form:

4x – 12y = 8

2.) Convert to standard form:

2 5 3

y x = −

B. Writing linear equations given the slope and y­intercept ­ Find the slope (m) and y­intercept (b) [If the given information is a graph, then you will have to count by hand to find these values.] ­ Fill in m and b so you have an equation of the line in y = mx + b form.

y = ________ x + ____________ (↑ Put m here!) (↑ Put b here!)

3.) Find the equation of the line with slope of 5 and y­intercept of ­2. Write in standard form.

4.) Find the equation of the given line in slope­intercept form.

5.) Write the equation of a line that has the same slope

as 4 3 5

y x = − and has a y­intercept

of 1. Write in standard form.

Page 20: Geometry Chapter 3 Notes - Canyon Crest Academy …teachers.sduhsd.net/chayden/documents/Chapter3Notes08.pdf · Geometry Chapter 3 Notes Notes #13: Section 3.1 and Algebra Review

­ 20 ­ C. Writing linear equations given the slope and a point

• plug slope = m into y = mx + b • name your point (x, y) and plug these values in for x and y • solve for b • plug m and b back into y = mx + b • convert to standard form, if necessary

** Remember to leave x and y as variables! ** 6.) Find the equation of the line with slope of ­2 and going through (­1, 3) in slope­intercept form.

7.) Find the equation of the

line with slope of 1 3 and

going through (6, ­2) in standard form.

8.) Find the equation of the line in slope­intercept form with

slope 2 5

− and passing through the

point (­3, 7).

D. Writing linear equations given two points • find the slope • pick one of your points to be x and y • plug m, x, y into y = mx + b • solve for b; plug m and b into y = mx + b • convert to standard form, if necessary

** Remember to leave x and y as variables! ** 9.) Find the equation of the line going through (­3, 1) and (4, 8) in slope­intercept form.

10.) Find the equation of the line with x­intercept 3 and y­intercept ­2 in standard form.

11.) Find the equation of the line going through (5, 2) and (­1, 3) in standard form.

12.) Find the equation of the line with x­intercept 5 and y­intercept ­4 in slope­intercept form.

Page 21: Geometry Chapter 3 Notes - Canyon Crest Academy …teachers.sduhsd.net/chayden/documents/Chapter3Notes08.pdf · Geometry Chapter 3 Notes Notes #13: Section 3.1 and Algebra Review

­ 21 ­ Notes #19: Section 3.7 A. Review ­ Writing Linear Equations: 1.) Find the equation of the line with slope of 3 4 and going through (1, 5) in slope­intercept

form.

2.) Find the equation of the line going through (­1, 0) and (4, 2) in slope­intercept form.

3.) Find the equation of the line with x­intercept ­1 and y­intercept 2 in standard form.

4.) Find the equation of the line going through (4, 3) with x­intercept 6 in standard form.

B. Parallel and Perpendicular Lines For #5­6, a pair of parallel lines and a pair of perpendicular lines are graphed below. Use the graphs to find the slope of each of the four lines and to complete the sentences.

5.)

­10­9 ­8 ­7 ­6 ­5 ­4 ­3 ­2 ­1 1 2 3 4 5 6 7 8 9 10 x

­10

­9 ­8

­7

­6 ­5

­4

­3 ­2

­1

1 2

3

4 5

6

7

8 9

10 y

Slope of 1 l : Slope of 2 l :

Parallel lines have _________ slopes.

Page 22: Geometry Chapter 3 Notes - Canyon Crest Academy …teachers.sduhsd.net/chayden/documents/Chapter3Notes08.pdf · Geometry Chapter 3 Notes Notes #13: Section 3.1 and Algebra Review

­ 22 ­

6.)

­10­9 ­8 ­7 ­6 ­5 ­4 ­3 ­2 ­1 1 2 3 4 5 6 7 8 9 10 x

­10

­9 ­8

­7

­6 ­5

­4

­3 ­2

­1

1 2

3

4 5

6

7

8 9

10 y

Slope of 3 l : Slope of 4 l :

Perpendicular lines have ____________, _____________ slopes.

The slope of a line is given. Find the slope of a line parallel to it and the slope of a line perpendicular to it:

7.) m = 2 3

− 8.) m = 7 9.) m = 0

Are the lines with these slopes parallel, perpendicular, or neither?

10.) 11.) ­4, 4 12.) ­1, 1

13.) Find the slope of a line parallel and perpendicular to AB suur

where A(­3, 1) and B (2, 4)

, 2 4 3 6

Page 23: Geometry Chapter 3 Notes - Canyon Crest Academy …teachers.sduhsd.net/chayden/documents/Chapter3Notes08.pdf · Geometry Chapter 3 Notes Notes #13: Section 3.1 and Algebra Review

­ 23 ­ For #14­16, state whether the given pair of lines is parallel, perpendicular, or neither:

14.) 3 1 4

8 6 12

y x

x y

= − +

− =

15.) 1 5 2

2 4 9

y x

x y

= − +

+ =

16.) 5 4 5 4

y x x y

= − + = − +

C. Writing linear equations given a point and another line (parallel or perpendicular to your line) • find m from the given line • if the line is parallel, this is your m;

if the line is perpendicular, find its ______________ _______________ • plug m, x, y into y = mx + b • solve for b; plug m and b into y = mx + b • convert to standard form, if necessary

** Remember to leave x and y as variables! ** 17.) Find the equation of the line going through (1, 2) and parallel to y = 3x + 4 in slope­intercept form.

18.) Find the equation of the line going through (3, ­2) and perpendicular to x – 4y = 3 in standard form.

19.) Find the equation of the line going through (­1, 5) and perpendicular to y = 3x + 4 in slope­ intercept form.

20.) Find the equation of the line going through (9, ­3) and parallel to 2x – 3y = 3 in standard form.

Page 24: Geometry Chapter 3 Notes - Canyon Crest Academy …teachers.sduhsd.net/chayden/documents/Chapter3Notes08.pdf · Geometry Chapter 3 Notes Notes #13: Section 3.1 and Algebra Review

­ 24 ­ Notes #20: Review You can now solve linear systems (a set of 2 lines) using algebra (substitution/elimination) AND using coordinate Geometry (graphing). You should get the same answer for both methods.

­ solve the equations using substitution or elimination; write your answer as a point ( , ) ­ graph the two lines using either the intercept method OR slope­intercept method ­ confirm that the two lines intersect (meet) at your solution point

1.) y = x – 2 x + y = 4

1 st Method: substitution or elimination

solution: ( , )

2 nd Method: graphing (graph both lines on the coordinate plane below)

­10­9 ­8 ­7 ­6 ­5 ­4 ­3 ­2 ­1 1 2 3 4 5 6 7 8 9 10 x

­10

­9 ­8 ­7

­6 ­5

­4 ­3 ­2

­1

1 2 3

4 5

6 7

8 9

10 y

2.) 2x – y = ­3 x + 2y = 6

1 st Method: substitution or elimination

solution: ( , )

2 nd Method: graphing (graph both lines on the coordinate plane below)

­10­9 ­8 ­7 ­6 ­5 ­4 ­3 ­2 ­1 1 2 3 4 5 6 7 8 9 10 x

­10 ­9 ­8 ­7

­6 ­5 ­4

­3 ­2

­1

1 2 3

4 5

6 7

8 9

10 y

Page 25: Geometry Chapter 3 Notes - Canyon Crest Academy …teachers.sduhsd.net/chayden/documents/Chapter3Notes08.pdf · Geometry Chapter 3 Notes Notes #13: Section 3.1 and Algebra Review

­ 25 ­ Chapter 3 Study Guide

For #1­4, identify whether the angles are vertical angles, same side interior angles, corresponding angles, alternate interior angles, same­side exterior angles, or alternate exterior angles. 1.) 2 and 6 ∠ ∠

3.) 5 and 2 ∠ ∠

2.) 1 and 6 ∠ ∠

4.) 4 and 7 ∠ ∠

7

6 5

4 3

2 1

For #5­6, find the slope of the line passing through the two points 5.) (­3, 2) and (4, 1) 6.) (­9, 2) and (2, 2) 7.) The slope of line l is

given. Find the slope of the line parallel to it and the slope of the line perpendicular to it: a) ­2 b) 3/2

For #8­10, name the two lines and transversal that form each pair of angles:

8.) 1, 3 ∠ ∠ lines: ____, ____ trans: ______

9.) , BAD CDA ∠ ∠ lines: ____, ____ trans: ______

10.) , 5 BAD ∠ ∠ lines: ____, ____ trans: ______

5 4 3

2 1

B

A

C

D E

In the diagrams, the lines shown are parallel. Write an equation and solve for x and y. (The answer to #12 is two fractions.) Justify your work.

2x+40

x+80 5y+20

11.)

2x+10 2y+20

y+65

12.)

Find the values of x and y. 13.)

40

20

y

x

14.)

5x

15x­20 5y

Page 26: Geometry Chapter 3 Notes - Canyon Crest Academy …teachers.sduhsd.net/chayden/documents/Chapter3Notes08.pdf · Geometry Chapter 3 Notes Notes #13: Section 3.1 and Algebra Review

­ 26 ­ Define your variables, write an equation, and solve: 15.) The sum of two numbers is 10. The difference of the first number and twice the second number is 1. Find the numbers.

In each exercise, some information is given. Use this information to name the segments that must be parallel. If there are no such segments, write none. 16.) 3 10 ∠ ≅ ∠

18.) 2 3 ∠ ≅ ∠

17.) 7 10 ∠ ≅ ∠

19.) 9 5 ∠ ≅ ∠ 11

10 9

8

7

6 5

4

3 2 1 A B

F C

E D

Solve for x and y: 20.)

6x ­ 2y 140

x + y

130

Solve for x and y: 21.)

1 1 1 2 4 2 1 8 3 2

x y

x y

+ = −

− = −

22.) Prove the converse of the alt ext angles theorem:

If two lines and a transversal form alternate exterior angles that are congruent, then the two lines are parallel.

Given: 1 3 ∠ ≅ ∠ Prove: m n P

n

m

3

2 1

Statements Reasons 1.)

2.)

3.)

4.)

1.)

2.)

3.)

4.)

Page 27: Geometry Chapter 3 Notes - Canyon Crest Academy …teachers.sduhsd.net/chayden/documents/Chapter3Notes08.pdf · Geometry Chapter 3 Notes Notes #13: Section 3.1 and Algebra Review

­ 27 ­ 23.) Given: l m P

Prove: 2 4 180 m m ∠ + ∠ = o 4 3

2 1

m

l

Statements Reasons 1.)

2.)

3.)

4.)

1.)

2.)

3.)

4.)

For #25­26, classify the triangles based on their sides and their angles: 25.) 23.)

2x 3x + 5

8x ­ 20

26.) 24.)

60 60

24.) Given: AB = CD AE = FD

Prove: EB = CF

A B

C D

E

F

Statements Reasons 1.)

2.)

3.)

4.) AE = FD

5.)

1.)

2.)

3.)

4.)

5.)

Page 28: Geometry Chapter 3 Notes - Canyon Crest Academy …teachers.sduhsd.net/chayden/documents/Chapter3Notes08.pdf · Geometry Chapter 3 Notes Notes #13: Section 3.1 and Algebra Review

­ 28 ­

Use the diagram for reference. Show all equations and work.

27.) If m 6 42 and m 8 61, then m 10 ____

∠ = ∠ = ∠ =

11

10

9

8

7 6

28.) If m 6 7 , m 7 2 5, and m 11 6 + 35, then = ___.

x x x

x

∠ = ∠ = + ∠ = 29.)

If m 8 7 2, m 7 4 7, and m 9 10 + 3, then = ___.

x x x

x

∠ = − ∠ = − ∠ =

For #30­31, a, b, c, and d are distinct coplanar lines. How are a and d related? 30.) , , a b b c c d ⊥ P P 31.) , , a b b c c d ⊥ ⊥ P

For #32­33, find the measure of an interior angle and an exterior angle of each regular polygon. 32.) an octagon 33.) a pentagon

Complete the table for regular polygons 34.) (a) (b) (c)

Work: (a) (b) (c)

Number of Sides 6 Sum of exterior angles Measure of each exterior angle 20 Measure of each interior angle 162 Sum of interior angles

Page 29: Geometry Chapter 3 Notes - Canyon Crest Academy …teachers.sduhsd.net/chayden/documents/Chapter3Notes08.pdf · Geometry Chapter 3 Notes Notes #13: Section 3.1 and Algebra Review

­ 29 ­ Graphing Linear Equations: 35.) Graph each line using the slope and y­ intercept:

a) y = ­ 3 2 x + 1 b) 2x + y = 4 c) 3x – 2y = 8

­10­9 ­8 ­7 ­6 ­5 ­4 ­3 ­2 ­1 1 2 3 4 5 6 7 8 9 10 x

­10

­9 ­8 ­7

­6 ­5

­4

­3 ­2

­1

1 2 3

4 5

6 7

8 9

10 y

36.) Graph the lines using the x and y intercepts:

a) 2x + 3y = 6 b) 3x – 5y = 15 c) 2x – 3y = 10

­10 ­9 ­8 ­7 ­6 ­5 ­4 ­3 ­2 ­1 1 2 3 4 5 6 7 8 9 10 x

­10

­9 ­8

­7

­6 ­5

­4

­3 ­2

­1

1 2

3

4 5

6

7

8 9

10 y

37. Find the x and y intercept of each line:

a) x + 2y = 6 b) 3x – 4y = 8 c) y = 1 2

− x + 3

38. Find the slope and y­intercept of each line: a) y = 3x – 5 b) y = 3 c) 3x – 2y = 4

39. Find the intersection of the two lines using the substitution or elimination method. x + 2y = 8 and 2x + 3y = 10

40. Explain why these two lines will not intersect y = 2x – 1 and 8x – 4y = 16

Writing Linear Equations: Write an equation of the line with: 41. y­intercept ­2 and slope ­4 in standard form 42. x­intercept 4 and y­intercept ­2 in slope­

intercept form

43. through (1, ­2) with slope ­3 in slope­ intercept form

44. through (6, 2) and parallel to x – 2y = 5 in standard form

Page 30: Geometry Chapter 3 Notes - Canyon Crest Academy …teachers.sduhsd.net/chayden/documents/Chapter3Notes08.pdf · Geometry Chapter 3 Notes Notes #13: Section 3.1 and Algebra Review

­ 30 ­

45. through (2, ­1) and perpendicular to x + 3y = 7 in standard form

47. through (3, ­2) and (7, ­2) in slope­intercept form

49. x­intercept ­3 and y­intercept 5 in standard form

46. through (3, 2) and (4, 7) in slope­intercept form

48. through (4, ­3) and with x­intercept ­2 in standard form

50. through (3, ­3) and perpendicular to 2x – y = 1 in slope­intercept form

For #51­53, are the given lines parallel, perpendicular, or neither?

51.) 1 2 3

2 6 10

y x

x y

= − +

− = 52.)

1 2 3

2 6 10

y x

x y

= − +

+ = 53.)

1 2 3

6 2 10

y x

x y

= − +

− =