1. 1.5 Exploring Angle Pairs 9/20/10
Types of Angle Pairs
Adjacent Angles
Vertical Angles
Complementary Angles
Supplementary Angles

2. Adjacent Angles
Adjacent angles – two coplanar angles with a common side, a common vertex, and no common interior points.

3. Vertical Angles
Vertical angles – two angles whose sides are opposite rays.

4. Complementary Angles
Complementary angles – two angles whose measures have a sum of 90°.
Each angle is called the complement of the other.

5. Supplementary Angles
Supplementary angles – two angles whose measures have a sum of 180°.
Each angle is called the supplement of the other.

6. Identifying Angle Pairs
Use the diagram. Is the statement true? Explain.
a are adjacent angles.
b are vertical angles.
c are complementary.

7. Identifying Angle Pairs
No, they are not adjacent. They have a common side and common vertex, but they also have common interior points.
No, they are not vertical angles. Ray FA and ray FD are opposite rays, but ray FE and ray FB are not.
Yes, they are complementary = 90°.

8. Linear Pairs
A linear pair is a pair of adjacent angles whose noncommon sides are opposite rays.
The angles of a linear pair form a straight angle.
Postulate 1.9 Linear Pair Postulate
If two angles form a linear pair, then they are supplementary.

9. Finding Missing Angle Measures
are a linear pair. What are the measures of ?

10. Finding Missing Angle Measures

11. Angle Bisector
An angle bisector is a ray that divides an angle into two congruent angles.
Its endpoint is at the angle vertex.
Within the ray, a segment with the same endpoint is also an angle bisector.
The ray or segment bisects the angle.

12. Using an Angle Bisector to Find Angle Measures
bisects If ,
what is

13. More Practice!!!!! Classwork – Textbook p. 38 # 7 – 25 odd.
Homework – Textbook p. 38 # 8 – 26 even.