Question

which angles are congruent to each other? ∠3 and ∠1 ∠4 and ∠1 ∠1 and ∠8 ∠5 and ∠6

Explanation:

Step1: Recall vertical - angle property

Vertical angles are congruent. When two lines intersect, the opposite angles are equal. In the given figure, $\angle3$ and $\angle1$ are vertical angles.

Step2: Analyze other angle pairs

$\angle4$ and $\angle1$ are adjacent angles, $\angle1$ and $\angle8$ are not related by a simple congruence rule in this non - parallel line intersection scenario, and $\angle5$ and $\angle6$ are adjacent angles.

Answer:

$\angle3$ and $\angle1$