Question

look at this diagram: if $overleftrightarrow{bd}$ and $overleftrightarrow{eg}$ are parallel lines and $mangle efc = 43^{circ}$, what is $mangle gfc$?

Explanation:

Step1: Recall angle - relationship

$\angle EFC$ and $\angle GFC$ are supplementary angles. Supplementary angles add up to $180^{\circ}$.

Step2: Set up the equation

Let $m\angle EFC = 43^{\circ}$ and $m\angle GFC=x$. Then $m\angle EFC + m\angle GFC=180^{\circ}$, so $43^{\circ}+x = 180^{\circ}$.

Step3: Solve for $x$

$x=180^{\circ}- 43^{\circ}=137^{\circ}$.

Answer:

$137$