1. 13.1 Angle Relationships

2. Complementary (They form a right angle.)
Complementary angles have a sum of 90 degrees.
(They form a right angle.)
Are the following angles complementary?
m<1 = 37° and m<2 = 43° ?
37° + 43° = 90°
80° ≠ 90°
No they are not complementary

3. Supplementary (They form a straight angle.)
Supplementary angles have a sum of 180 degrees.
(They form a straight angle.)
Are the following angles supplementary?
m<1 = 121° and m<2 = 59° ?
121° + 59° = 180°
180° = 180°
Yes they are supplementary

4. Are the following angles complementary, supplementary, or neither?
m<3 = 98° and m<4 = 82°
98° + 82°
= 180°
Supplementary

5. Are the following angles complementary, supplementary, or neither?
m<3 = 33.1° and m<4 = 67.9°
33.1° °
= 101°
Neither

6. Are the following angles complementary, supplementary, or neither?
m<1 = 54.65° and m<2 = 35.35°
= 90°
54.65° °
Complementary

7. Find the missing angle measure
39° + x° = 90°
-39° °
39°
x = 51°

8. Find the missing angle measure
21° + x° = 180°
21°
-21° °
x = 159°

9. Find the value of x. Then find the unknown angle measure.
32°
x = 37°
4x = 148°

10. Find the value of x. Then find the unknown angle measures.
3x° + 6x° = 90°
6x°
9x° = 90°
3x°
x = 10°
3x = 30°
6x = 60°

11. Vertical Angles
Angles that are opposite each other from intersecting lines
108°
Vertical angles are equal to each other
72°
72° x°
108°

12. Find the value of x.
5x - 1° = 64°
64°
5x° = 65°
(5x-1)°
x = 13°

13. Find the indicated angle measures
25º
25° 1 3
m<5 =
180º - 112º 2
m<5 = 68º
4x° 7 6 4 9 8
m<7 = xº
112° 5