Question

A pair of parallel lines is cut by a transversal:

A pair of parallel lines cut by a transversal is shown. The inside bottom right angle is labeled 80 degrees. The alternate interior angle is cut by a ray and is labeled as x on one side and 15 degrees on the other.

What is the measure of angle x?
60 degrees
65 degrees
70 degrees
80 degrees

Answer 1

Alternate interior angles are equal, thus the given alternate interior angle is 80 degrees.
Therefore, x = 80 - 15 = 65 degrees.