line XY is parallel to line WV because angle 2 is equal to angle 3
For angles to be equal for some reasons like corresponding angles , alternate and vertical angles, they must be angles formed by parallel lines.
In the diagram
angle 1 is congruent to angle 2 : given
angle 3 is congruent to angle 1 : given
angle 2 is congruent to angle 3 : alternate angles.
Therefore, line XY is parallel and similar to line WV.