Question

1. in the diagram below, m∠1 = 63°. what is m∠3 and give the geometric reason?

Explanation:

Step1: Identify angle - relationship

$\angle1$ and $\angle3$ are vertical angles.

Step2: Apply vertical - angle property

Vertical angles are congruent. Since $m\angle1 = 63^{\circ}$, then $m\angle3=m\angle1$.

Answer:

$m\angle3 = 63^{\circ}$, because vertical angles are congruent.