Question

which angle number represents an angle vertical to ∠vyu?

Explanation:

Step1: Recall vertical - angle definition

Vertical angles are formed when two lines intersect. They are opposite each other and have equal measures.

Step2: Identify intersecting lines and vertical angles

Lines $VW$ and $TS$ intersect at point $Y$. $\angle VYU$ and $\angle WYT$ are vertical angles. In terms of the numbered angles, $\angle VYU$ is angle $6$ and its vertical - angle $\angle WYT$ is angle $5$.

Answer:

$5$