This document contains notes on parallel lines and angle relationships formed when lines are cut by a transversal. It defines corresponding angles, alternate interior angles, alternate exterior angles, consecutive interior angles, and vertical and linear angles. Examples are given to demonstrate using corresponding angles and consecutive interior angles properties to solve for missing angle measures. Students are assigned a worksheet on angle pairs and problems from the textbook.

1. Warm-up
Name the angle pair relationships.
1 and 6 - Corresponding
1
2 and 7 - Alternate Exterior 3 2
3 and 5 - Alternate Interior 4
6
4 and 5 - Consecutive Interior 7 5
8
6 and 7 - Linear
1 and 4 - Vertical
Benchmark #12!!
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2. Geometry Notes
3.1 - Properties of Parallel Lines
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3. Parallel Line
Theorems
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4. Corresponding Angles
Postulate
If t wo lines are parallel
(and cut by a transversal),
then the corresponding
angles are congruent.
(Postulate 3-1)
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5. Alternate Interior Angles
Theorem
If t wo lines are parallel,
then the alternate interior
angles are congruent.
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6. Alternate Exterior
Angles Theorem
If t wo lines are parallel,
then the alternate exterior
angles are congruent.
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7. Same-Side Interior
Angles Theorem
If t wo lines are parallel,
then the consecutive
interior angles are
supplementary.
Also works with Same-Side
Exterior Angles
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8. So which is which?
adds to 180
≅ (Congruent) (supplementary)
•corresponding •same-side
•alternate interior ✤
interior
✤
✤exterior
✤exterior
•vertical •linear
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9. Examples
Example 1: Example 2:
Find the missing Solve for x.
angles.
75° y 89
x
5x-24
x=75° because it is 89 + 5x-24 = 180°
(Consecutive angles are
corresponding with 75°. Supplementary)
y=75° because it is 5x + 65 = 180
alternate exterior 5x = 115
with x. x = 23°
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10. How to set it up:
Decide what kind of angle
relationship
Decide ≅ or _ + _ = 180
Set it and Solve it
Check it
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11. Assignments:
Angle Pairs Worksheet
#16 p. 131 #1-13 (odd), 14-17,
19-22
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