Question

if one angle of a pair of consecutive interior angles is 120 degrees, what is the measure of the other angle?
a. 60 degrees
b. 120 degrees
c. 80 degrees
d. 100 degrees

Explanation:

Step1: Recall property of consecutive interior angles

Consecutive interior angles are supplementary, i.e., their sum is 180 degrees.

Step2: Set up the equation

Let the unknown angle be $x$. We have $x + 120^{\circ}=180^{\circ}$.

Step3: Solve for the unknown angle

$x=180^{\circ}- 120^{\circ}=60^{\circ}$.

Answer:

A. 60 degrees