Given the following figure, find .
Step 1: Find .
and are supplementary angles because they form a straight angle , so we can find by subtracting from .
Step 2: Find .
is formed by 2 equal angles, and , so we can find the measure of either equal angle by dividing by 2.
Step 3: Find .
and are opposite vertical angles, so the measures of the angles are equal to each other.