Question

which angle is vertical to ∠gcd?

Explanation:

Step1: Recall vertical - angle definition

Vertical angles are formed when two lines intersect. They are opposite each other and are congruent.

Step2: Identify intersecting lines

Lines $\overleftrightarrow{FG}$ and $\overleftrightarrow{AB}$ intersect at point $C$.

Step3: Determine vertical angle

The angle vertical to $\angle GCD$ is $\angle FCE$ because they are opposite each other at the intersection of the two lines.

Answer:

$\angle FCE$