Question

The measures of two supplementary angles are (2x + 10)° and (8x + 10)°.

What is the measure of the larger angle?
A.
16°
B.
44°
C.
14°
D.
138°

Answer 1

(2x + 10)° PLUS (8x + 10)° = 180

10x + 20° = 180

10x = 160

x = 16

The larger angle is (8x + 10)°

When we substitute x = 16 we get:

138°

Answer is D

Explanation:

Answer 2

D

Explanation:

Supplementary angles sum to 180°, hence

2x + 10 + 8x + 10 = 180

10x + 20 = 180 ( subtract 20 from both sides )

10x = 160 ( divide both sides by 10 )

x = 16

larger angle = 8x + 10 = (8 × 16) + 10 = 128 + 10 = 138°