Question

1. find the measure of c°. 159° a° b° c° e° d° 60° 21° 100.5° 159°

Explanation:

Step1: Use vertical - angle property

Vertical angles are equal. The angle of $159^{\circ}$ and angle $d$ are vertical angles, so $d = 159^{\circ}$.

Step2: Use linear - pair property

Angles $d$ and $e$ form a linear pair. Since the sum of angles in a linear pair is $180^{\circ}$, then $e=180 - 159=21^{\circ}$.

Step3: Use corresponding - angle property

Angles $e$ and $c$ are corresponding angles. Corresponding angles formed by a transversal intersecting two parallel lines are equal. So $c = e=21^{\circ}$.

Answer:

$21^{\circ}$