Answer: Below are the 3 reasons for the statement given in the proof.
2) Multiplication Property of Equality. In this this all the person did was rearrange the statement given in line 1 of the problem. They did this to show that the sides are proportional.
3) Vertical Angles are Congruent. Angles on opposite sides of intersecting lines are congruent.
4) SAS Similarity Theorem. If a triangle has two sides that are proportional with another triangle and the included angles are congruent, then the triangles are similar.