Question

Two angles are supplementary. The first angle measures 60°. What is the measurement of the second angle?
A. 90°
B. 30°
C. 120°
D. 180°

Answer 1

Supplementary angles are two angles that have a sum of 180°. 

If the first angle measures 60°, then the second angle is 120°.

180° - 60° = 120°  Choice C.