1. Chapter 1 Exploring Geometry: Points, Lines, and Angles in the Plane
Section 5
Complementary and Supplementary Angles
Objectives:
Students will be able to identify, complementary, supplementary, vertical, and adjacent angles and find missing measures.

2. Section 5 - Complementary and Supplementary Angles
Adjacent Angles
Adjacent angles are two angles that lie in the same plane and have a common side and a common vertex but no common interior points. 1 2 A B O C
1 and 2 are adjacent angles.
mAOB + mBOC = mAOC
Chapter 1
Section 5 - Complementary and Supplementary Angles

3. Section 5 - Complementary and Supplementary Angles
Complementary Angles
Complementary angles are two angles whose sum is 90°. A B
40°
50° 1 2
1 and 2 are complementary angles. They also form adjacent angles.
m1 + m2 = 90°
A and B are complementary angles.
mA + mB = 90°
Chapter 1
Section 5 - Complementary and Supplementary Angles

4. Section 5 - Complementary and Supplementary Angles
Supplementary angles are two angles whose sum 180°. C D
30°
150° 3 4
3 and 4 are supplementary angles. They also adjacent. Angles that are adjacent and supplementary are are called a linear pair.
m3 + m4 = 180°
C and D are supplementary angles.
mC + mD = 180°
Chapter 1
Section 5 - Complementary and Supplementary Angles

5. Section 5 - Complementary and Supplementary Angles
Vertical Angles
When two lines intersect four angles are formed.
Vertical angles are two nonadjacent angles formed by two intersecting lines.
Vertical angles are congruent. 5 8 7 6
5 and 6 are vertical angles.
7 and 8 are vertical angles.
5  6 & 7  8
Chapter 1
Section 5 - Complementary and Supplementary Angles