Question

tell which angles are congruent to the given angle meas 1 m||n

Explanation:

Step1: Identify vertical - angles

Vertical angles are congruent. Angle 1 and the given 100 - degree angle are vertical angles, so $\angle1 = 100^{\circ}$.

Step2: Identify corresponding angles

Since $m\parallel n$, corresponding angles are congruent. The given 100 - degree angle and $\angle5$ are corresponding angles, so $\angle5=100^{\circ}$.

Step3: Identify alternate - exterior angles

Alternate - exterior angles are congruent for parallel lines. The given 100 - degree angle and $\angle7$ are alternate - exterior angles, so $\angle7 = 100^{\circ}$.

Step4: Use vertical - angle relationship for $\angle7$

Since $\angle7$ and $\angle3$ are vertical angles, $\angle3=100^{\circ}$.

Answer:

$\angle1,\angle3,\angle5,\angle7$