Angles a and b are supplementary angles. What is the value of m a if m b = 43 degrees?

A. 223 degrees
B. 47 degrees
C. 43 degrees
D. 137 degrees

1 answer

D. 137 degrees

Supplementary angles add up to 180 degrees, so if angle b is 43 degrees, then angle a would be:

m a + m b = 180
m a + 43 = 180
m a = 180 - 43
m a = 137 degrees