Triangle Congruence 0B288E
1. **State the problem:** We need to complete the proof that $\triangle VYZ \cong \triangle WXZ$ given that $\triangle VWZ$ and $\triangle XYZ$ are equilateral triangles.
2. **Recall given information:**
- $\triangle VWZ$ is equilateral.
- $\triangle XYZ$ is equilateral.
- From these, we know $VZ \cong WZ$ and $XZ \cong YZ$ because all sides in equilateral triangles are equal.
- Also, $\angle VZY \cong \angle WZX$ by the Vertical Angle Theorem.
3. **Step 6: Identify the next congruent parts and reason:**
- Statement: $YZ \cong XZ$
- Reason: Sides opposite equal angles in equilateral triangles are equal (or by the definition of equilateral triangles, all sides are equal).
4. **Step 7: Use a congruence postulate to conclude:**
- Statement: $\triangle VYZ \cong \triangle WXZ$
- Reason: Side-Angle-Side (SAS) Postulate, since we have two pairs of sides and the included angle congruent.
Thus, the completed proof steps 6 and 7 are:
6. $YZ \cong XZ$
Reason: Definition of equilateral triangle (all sides equal).
7. $\triangle VYZ \cong \triangle WXZ$
Reason: SAS Postulate.
Final answer: $\triangle VYZ \cong \triangle WXZ$ by SAS.