Question

Let mA = 40°. If B is a complement of A, and C is a supplement of B, find these measures.

Answer 1

If B is a complement of A this means that the sum of the measures of A and B is 90 degrees.
             
mA + mB = 90
                  mB =90 - mA
                  mB = 90 - 40 = 50

Thus, the measure of angle B is 50 degrees. 

If C is a supplement of B then, the sum of the measures of B and C is 180 degrees. 
                mC + mB = 180
                mC = 180 - mB
                 mC = 180 - 50 = 130

Therefore, the measure of angle C is 130 degrees. 

Answer 2

the answer is

mb =50

mc=130