Question

Angles ​A​ and ​B​ are supplementary. If ​m​∠​A​ = 45°, find ​m​∠​B​.

A. 45°
B. 145°
C. 135°
D. 15°

Answer 1

If Angles are supplementary, means they both add up to 180 degrees.

A + B = 180°

45 + B = 180°

B = 180° - 45°

B = 135°

Option C.

Answer 2

supplementary means they add to 180

a+b=180
a=45
45+b=180
minus 45 both sides
b=135

answer is C