Part 2: Use congruency theorems to prove congruency.
The congruency of △MNO and △XYZ can be proven using a reflection across the line bisecting OZ. However, this congruency can also be proven using geometric postulates, theorems, and definitions. Prove that the triangles are congruent using a two-column proof and triangle congruency theorems.

Given: M ≅ X
N ≅ Y
YO ≅ NZ
Prove: △MNO ≅ △XYZ