Observe the given figure.
Given: WXYZ is a parallelogram and [tex]ZX \cong WY[/tex]
To Prove: WXYZ is a rectangle
Statements
1. WXYZ is a parallelogram and [tex]ZX \cong WY[/tex]
Reason: Given
2. [tex]ZY \cong WX[/tex]
Reason: Opposite sides of parallelogram are equal.
3. [tex]YX \cong YX[/tex]
Reason: Reflexive
4. [tex]\Delta ZYX \cong \Delta WXY[/tex]
Reason: By SSS congruence theorem
5. [tex]\angle ZYX \cong \angle WXY[/tex]
Reason: CPCT
6. [tex]m \angle ZYX \cong m \angle WXY[/tex]
Reason: Def of congruency
7. [tex]m \angle ZYX + m \angle WXY= 180^\circ[/tex]
Reason: Consecutive angles in a parallelogram are supplementary.
"If a quadrilateral is a parallelogram, it has consecutive angles then they are supplementary".
8. [tex]m \angle ZYX + m \angle ZYX= 180^\circ[/tex]
Reason: Substitution.
9. [tex]2(m \angle ZYX)= 180^\circ[/tex]
Reason: Simplification
10. [tex]m \angle ZYX = 90^\circ[/tex]
Reason: Division property of Equality
11. WXYZ is a rectangle
Reason: Rectangle angle theorem