Question

look at this diagram: if $overleftrightarrow{ce}$ and $overleftrightarrow{fh}$ are parallel lines and $mangle cdg = 123^{circ}$, what is $mangle fgi$?

Explanation:

Step1: Identify angle - type relationship

$\angle CDG$ and $\angle FGI$ are vertical angles.

Step2: Apply vertical - angle property

Vertical angles are congruent. So $m\angle FGI=m\angle CDG$.

Answer:

$123$