Question

review the diagram.
ef and gh are parallel.
ef and gh are intersected by line t.
select the pair of angles which are vertical angles.

Explanation:

Step1: Recall vertical - angle definition

Vertical angles are opposite angles formed by the intersection of two lines.

Step2: Analyze the diagram

In the given diagram where $\overline{EF}$ and $\overline{GH}$ are intersected by line $t$, $\angle1$ and $\angle3$ are opposite angles formed by the intersection of the two - line intersection, and also $\angle2$ and $\angle4$ are opposite angles. Similarly, $\angle5$ and $\angle7$, $\angle6$ and $\angle8$ are vertical - angle pairs.

Answer:

There are multiple pairs such as $\angle1$ and $\angle3$, $\angle2$ and $\angle4$, $\angle5$ and $\angle7$, $\angle6$ and $\angle8$.