Question

< A and < B are supplementary angles. If m m < B= (2x+30), then find the measure of < A.

Answer 1

m<A = 50°

Explanation:

supplementary angles add up to 180°

m<B = 2x + 30

we don't know m<A, so we'll say the value of it is x

2x + 30 + x = 180°

3x + 30 = 180

3x = 150

x = 50

plug this value back in for x

m<B = 2(50) + 30 = 130

m<B = 130°

m<A = x = 50

m<A = 50°

to prove these are supplementary angles, 130 + 50 = 180