1. Goal: Find the measures of angles formed by intersecting lines.
2.4 Vertical Angles
Goal:
Find the measures of angles formed by intersecting lines.

2. Key Words Vertical angles Linear pair
Two angles that are nonadjacent and their sides are formed by two intersecting lines.
Linear pair
Two adjacent angles whose non-common sides are on the same line.

3. Identify Vertical Angles and Linear Pairs
1. Determine whether the labeled angles are vertical angles, a linear pair or neither.
Linear Pair
Neither
Vertical Angles

4. Postulate 7 Linear Pair Postulate
If two angles form a linear pair, then they are supplementary. 1 2

5. Use the Linear Pair Postulate
2. Find the measure of

6. Theorem 2.3 Vertical Angles Theorem Vertical angles are congruent 2 31 4

7. Use the Vertical Angles Theorem
3. Find the measure of

8. Find Angle Measures
4. Find

9. Use Angles with Vertical Angles
5. Find the value of y

10. Homework
2.4 pg. 78
10-40 Even, 41-50, Even