Use the relationship between supplementary angles ∠a

and ∠b
. What is m∠a if m∠b=121° ?(1 point)
Responses

121°
121 degrees

301°
301 degrees

31°
31 degrees

59°

Since ∠a and ∠b are supplementary angles, the sum of their measures is equal to 180 degrees.

So, m∠a = 180° - m∠b = 180° - 121° = 59°