Question

look at this diagram: if $overleftrightarrow{hj}$ and $overleftrightarrow{km}$ are parallel lines and $mangle hig = 60^{circ}$, what is $mangle jig$?

Explanation:

Step1: Recall angle - addition property

$\angle HIG+\angle JIG = 180^{\circ}$ (linear - pair of angles, since $\overrightarrow{HJ}$ is a straight - line).

Step2: Solve for $\angle JIG$

Given $\angle HIG = 60^{\circ}$, then $\angle JIG=180^{\circ}-\angle HIG$. Substitute $\angle HIG = 60^{\circ}$ into the equation: $\angle JIG = 180 - 60=120^{\circ}$.

Answer:

$120$