Answer:
Similar Triangles must have matching angles, so you need to prove the angles all match.
Step-by-step explanation:
1.
Angle RTW = Angle STV becasue it's the same angle.
2.
Because ST is parallel to RW and RT cuts through those two parallel lines, you have
Angle TSV = Angle TRW because they are corresponding angles.
3.
Because ST is parallel to RW and TW cuts through those two parallel lines, you have
Angle TVS = Angle TWR because they are corresponding angles.
So now you know the three angles in each triangle match the three angles in the other triangle. They're similar triangles.
