Question

A and B are supplementary angles. If A=(3x-17) and B = (2x-23), then find the measure of B

Answer 1

B = 65°

Explanation:

Two "supplementary" angles add up to 180 degrees.

Therefore:

A + B = 180

(3x - 17) + (2x - 23) = 180

"Combine like terms" on the left side: the Xs and the numbers.

3x + 2x - 17 - 23 = 180

5x - 40 = 180

Add 40 to both sides:

5x = 220

And divide 5 on both sides:

x = 44

But we're looking for B, which is

(2x - 23) = 2(44) - 23 = 88 - 23 = 65

B = 65°