Answer:
1. L || m - Given in the question
2. ∠ 1 ≅ ∠ 3 - Since L || m, we can see in the image that ∠1 is corresponding to ∠3 since corresponding angles are the angles which occupy the same relative position at each intersection where a straight line crosses two others
3. ∠1 ≅ ∠2 - From the image, we can see that ∠1 is vertically opposite to ∠2, Hence ∠1 ≅ ∠2
4. ∠2 ≅ ∠3 - From the image, we can see that ∠2 and ∠3 are alternate angles, since alternate angles are angles that are in opposite positions relative to a transversal intersecting two lines.