Question

look at this diagram: if $overleftrightarrow{bd}$ and $overleftrightarrow{eg}$ are parallel lines and $mangle efc = 66^{circ}$, what is $mangle bca$?

Explanation:

Step1: Identify angle - relationship

$\angle EFC$ and $\angle BCA$ are vertical angles.

Step2: Recall vertical - angle property

Vertical angles are congruent. So $m\angle BCA=m\angle EFC$.

Answer:

$66$