If 2 angles and the included side of one triangle are congruent to 2 angles and the included side of another triangle , then the triangles are congruent.
The included side is the side between the vertices of the 2 angles.
∠ U = ∠ V ( given )
∠ VWU = ∠ YWX ( vertical angles )
The included sides UW and WY are also congruent ( given )
Thus Δ VUW and Δ XYW are congruent by the ASA postulate