Question

look at this diagram: if $overleftrightarrow{ik}$ and $overleftrightarrow{ln}$ are parallel lines and $mangle ijh = 51^{circ}$, what is $mangle kjh$?

Explanation:

Step1: Recall angle - addition property

$\angle IJH$ and $\angle KJH$ form a linear - pair.

Step2: Use linear - pair property

The sum of the measures of angles in a linear - pair is $180^{\circ}$. So, $m\angle IJH + m\angle KJH=180^{\circ}$.

Step3: Solve for $m\angle KJH$

Given $m\angle IJH = 51^{\circ}$, then $m\angle KJH=180^{\circ}-m\angle IJH$. Substitute $m\angle IJH = 51^{\circ}$ into the equation: $m\angle KJH = 180 - 51=129^{\circ}$.

Answer:

$129$