Question

lines a and b are parallel. what is the measure of ∠7 if ∠2 measures 68°? a 34° b 56° c 68° d 112°

Explanation:

Step1: Identify angle - pair relationship

$\angle2$ and $\angle4$ are vertical angles, so $\angle4=\angle2 = 68^{\circ}$.

Step2: Use parallel - line property

Since lines $a$ and $b$ are parallel, $\angle4$ and $\angle7$ are alternate exterior angles. Alternate exterior angles are congruent when the lines are parallel. So $\angle7=\angle4$.

Answer:

C. $68^{\circ}$