Question

Given the following diagram, find the required measure.

Given: m∠3 = m∠7
m∠2 = 60°
m∠6 = 115°

m∠1 =

A. 110
B. 120
C. 125
D. 130

Answer 1

m<2 = 60
m<1 = 180 - 60
m<1 = 120

answer
B. 120

Answer 2

B. 120°

Explanation:

Angles 1 and 2 are supplementary. Therefore

m∠1 + m∠2 = 180°

m∠1 = 180° - m∠2

m∠1 = 180° - 60°

m∠1 = 120°

The angles with measures m∠1 and m∠2 are supplementary because they lie along a straight line. Since straight angles have measures of 180°, the angles are supplementary.