Question

which angles are congruent to each other? ∠9 and ∠12 ∠6 and ∠2 ∠2 and ∠4 ∠3 and ∠6

Explanation:

Step1: Recall vertical - angle property

Vertical angles are congruent. $\angle9$ and $\angle12$ are vertical angles.

Step2: Analyze other angle pairs

$\angle6$ and $\angle2$ are not vertical angles and no parallel - line relationship is given to suggest congruence. $\angle2$ and $\angle4$ are adjacent angles, not congruent in general. $\angle3$ and $\angle6$ are not vertical angles and no parallel - line relationship is given to suggest congruence.

Answer:

$\angle9$ and $\angle12$