Question

The intersection of three lines at one point and the measures of three angles are shown in this figure.

Answer 1

D. 2x+71=180

Explanation:

Six angles are represented, three are marked. The six angles add up to 360 (360 degrees in a circle). We know that the sum of all the marked angles equals 180, because each marked angle has an equal, unmarked, vertically opposite angle, and half of 360 is 180. Therefore we can write:

76+(x-5)+x=180

2x+71=180