1. Objective: To identify complementary, supplementary,
alternate interior, corresponding, and vertical angles.
4.12.6
Class Notes Geometry Sec 2.3
1. Complementary Angles: 2 angles that add up to 90
20
Are these two angles
adjacent or
non-adjacent?
20
70
15 A B C D
Example 1: Find the measure of
a. ABD
b. ABC
c. DBC

2. 3. Supplementary Angles: 2 angles that add up to 180
Are these two angles
adjacent or
non-adjacent?
Are these two angles
adjacent or
non-adjacent?
20
20
160
4. Example 2: Find the measure of
ACB
ACD
c. DCB
13 A B C D

3. 5. Find the measure of all the unknown angles.
37 A B C D E F
128 G H
6. Find x
7. Find the measure of the
acute angle.
4x-52
2x-4
8. Find the measure of the
obtuse angle.

4. 9. Find x
3x + 7
2x + 18
10. Find the measure of the
acute angle.
11. Find the measure of the
obtuse angle.