Given: WZ || XY, WX || ZY, WZ = ZY
Prove: WXYZ is a rhombus
Statements
1. WZ || XY (Given)
2. WX || ZY (Given)
3. WZ = ZY (Given)
4. ∠WZY = ∠WXY (Alternate Interior Angles Theorem)
5. ∠WXY = ∠WYZ (Alternate Interior Angles Theorem)
6. ∠WYZ = ∠WZY (Vertical Angles Theorem)
7. ∠WZY = ∠WXY = ∠WYZ (Transitive Property of Equality)
8. WXYZ is a parallelogram (Definition of a parallelogram)
9. WXYZ is a rhombus (Definition of a rhombus)
Reasons
1. Given
2. Given
3. Given
4. Alternate Interior Angles Theorem
5. Alternate Interior Angles Theorem
6. Vertical Angles Theorem
7. Transitive Property of Equality
8. Definition of a parallelogram
9. Definition of a rhombus