2.2/2.4: Complementary & Supplementary Angles

Day 3

I can recognize complementary angles.

I can recognize supplementary angles.

Defn: Complementary angles are two angles that add up to 90 degrees.

Each of the two angles is called the complement of the other.

Defn: Supplementary angles are two angles that add up to 180 degrees.

Each of the two angles is called the supplement of the other.

Example 1

Given:Prove: are complementary

angles

AB BCABDand CBD

B

A

C

D

Example 2

Find the complement and supplement of a 93 degree angle.

Example 3

One of two complementary angles is three times the other. Find the angles.

Example 4

The larger of two supplementary angles is 30 degrees more than twice the other angle. Find both angles.

Example 5

Two supplementary angles are in the ratio of 2:3. Find the larger supplement.

2.4 Congruent Supplements and Complements

Example 1:

B CA

45

Given: BA Supp

A CSupp

Find: m B m Cand

Congruent Supplements:( )

Congruent Complements:( )

Two angles are congruent if they are supplementary to the same angle or supplementary to congruent angles.

Two angles are congruent if they are complementary to the same angle or complementary to congruent angles.

1

2

3

4

5 8

6 7

Example 2:

Given: 74 comp

1 50m

Find the measure of all the angles below

Example 3:

One of two supplementary angles is eight times the measure of the other. Find the measure of the complement of the smaller angle.