m∠ 1 = 140° by the Vertical Angles Congruence Theorem.
m∠ 2 = 40° by the Corresponding Angles Theorem.
The image shows two parallel lines intersected by a transversal. We are asked to find the measure of two angles,∠1 and ∠2, and to identify the theorems used in the process.
Find ∠ 1
We see that ∠1 and the angle marked 140° are vertical angles. Vertical angles are congruent, so ∠1 = 140°.
Find ∠ 2
∠2 and the angle marked 40° are corresponding angles. Corresponding angles are congruent, so ∠2 = 40°.