Proof: Rectangle Right Angles 3

Let's prove the following theorem:

Proof:

Proof Table

#	Claim	Reason
1	WXYZ is a parallelogram	if WXYZ is a rectangle, then WXYZ is a parallelogram (Rectangle Property)
2	WZ || XY	if WXYZ is a parallelogram, then WZ || XY (Parallelogram Property 3)
3	∠XYZ is a right angle	if WXYZ is a rectangle, then ∠XYZ is a right angle (Rectangle Right Angles 2)
4	∠WZY and ∠ZYX are supplementary	if WZ || XY, then ∠WZY and ∠ZYX are supplementary (Interior Angles of Parallel Lines)
5	(m∠WZY) + (m∠ZYX) = 180	if ∠WZY and ∠ZYX are supplementary, then (m∠WZY) + (m∠ZYX) = 180 (Supplementary Angles Property)
6	m∠XYZ = 90	if ∠XYZ is a right angle, then m∠XYZ = 90 (Right Angle Property)
7	m∠ZYX = m∠XYZ	m∠ZYX = m∠XYZ (Angle Symmetry Property)
8	m∠ZYX = 90	if m∠ZYX = m∠XYZ and m∠XYZ = 90, then m∠ZYX = 90 (Transitive Property of Equality)
9	(m∠WZY) + 90 = 180	if (m∠WZY) + (m∠ZYX) = 180 and m∠ZYX = 90, then (m∠WZY) + 90 = 180 (Substitution Example 10)
10	m∠WZY = 90	if (m∠WZY) + 90 = 180, then m∠WZY = 90 (Add Number to Both Sides)
11	m∠YZW = 90	if m∠WZY = 90, then m∠YZW = 90 (Angle Symmetry Example 2)
12	∠YZW is a right angle	if m∠YZW = 90, then ∠YZW is a right angle (Right Angle Property (Converse))

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