Question

in the figure below, m∠1 = 60°. find m∠2.

Explanation:

Step1: Note angle - sum property

$\angle1$ and $\angle2$ form a straight - line pair, so $\angle1+\angle2 = 180^{\circ}$.

Step2: Solve for $\angle2$

$\angle2=180^{\circ}-\angle1$.
Substitute $\angle1 = 60^{\circ}$, then $\angle2=180 - 60=120^{\circ}$.

Answer:

$120$