1. Complementary and Supplementary Angles
Section 2.2
Elena de Soto

2. Complementary and Supplementary Angles
Often times we see angles that measures add up to either a right angle or a straight angle. These are Complements and Supplements.

3. Video on Complementary Angles http://youtube. com/watch
Video on Complementary Angles Video on Supplementary Angles

4. Complements
Complementary angles are two angles whose sum is 90° (or a right angle). Each of the two angles is called the complement of the other.

5. Practice
Find the complement of 58°
Answer=32°

6. Supplements
Supplementary angles are two angles whose sum is 180° (or a straight angle). Each of the two angles is called the supplement of the other

7. Practice
Find the supplement of 139°
Answer=41°

8. Sample Proof

9. Algebraic Problems
An angle and its complement add to a right angle. An angle and its supplement add to a straight angle. Since a right angle is 90 degrees and a straight angle is 180 degrees.
The complement of an angle x degrees is (90 - x) degrees.
The supplement of an angle x degrees is (180 - x) degrees.

10. Algebraic Formula

11. Find the measure of XVS
Answer=60°

12. More Practice Problems
For more practice problems, it is recommended to try book page 70 #12-24

13. Works Cited
Angles in Geometry. 25 Nov Analyze Math. 29 May 2007 <
Rhoad, Richard. Geometry for Enjoyment and Challenge. Illinois: McDougal Littell, 1991.
The Math Forum. Drexel. 29 May 2007 <