Question

ZA and ZB are supplementary angles. If m_A = (5x + 25)° and mZB = (x +17)°, then find the measure of ZA.

Answer 1

Given that ∠A and ∠B are supplementary, then

m∠A + m∠B = 180°

Substituting with data:

(5x + 25) + (x + 17) = 180

(5x + x) + (25 + 17) = 180

6x + 42 = 180

6x = 180 - 42

6x = 138

x = 138/6

x = 23

Replacing this result into m∠A equation:

m∠A = (5x + 25)°

m∠A = (5(23) + 25)°

m∠A = (115+ 25)°

m∠A = 140°