Question

solve for x and then find the measure of angle b

Answer 1

A and B are the alternate angles. Alternate angles are congruent.

m∠A = m∠B, therefore we have the equation:

5x - 15 = 2x + 21      |+15

5x = 2x + 36      |-2x

3x = 36     |:3

x = 12

m∠B = 2x + 21 → m∠B = 2(12) + 21 = 24 + 21 = 45

Amswer: m∠B = 45°

Answer 2

Step-by-step explanation:

A = B ( exterior altermate)

5x - 15 = 2x + 21

3x = 36

x = 12

B = 24 + 21 = 45⁰