Question

1. identify the three correct angles that are congruent to ∠1.

Explanation:

Step1: Identify vertical - angle relationship

Vertical angles are congruent. $\angle1$ and $\angle3$ are vertical angles, so $\angle1\cong\angle3$.

Step2: Identify corresponding - angle relationship

Corresponding angles formed by parallel lines and a transversal are congruent. $\angle1$ and $\angle5$ are corresponding angles, so $\angle1\cong\angle5$.

Step3: Identify alternate - exterior - angle relationship

Alternate - exterior angles formed by parallel lines and a transversal are congruent. $\angle1$ and $\angle7$ are alternate - exterior angles, so $\angle1\cong\angle7$.

Answer:

$\angle3$, $\angle5$, $\angle7$