Proof: Rectangle Right Angles 2

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	WX || ZY	if WXYZ is a parallelogram, then WX || ZY (Parallelogram Property 2)
3	∠WXY is a right angle	if WXYZ is a rectangle, then ∠WXY is a right angle (Rectangle Property)
4	∠WXY and ∠XYZ are supplementary	if WX || ZY, then ∠WXY and ∠XYZ are supplementary (Interior Angles of Parallel Lines)
5	(m∠WXY) + (m∠XYZ) = 180	if ∠WXY and ∠XYZ are supplementary, then (m∠WXY) + (m∠XYZ) = 180 (Supplementary Angles Property)
6	m∠WXY = 90	if ∠WXY is a right angle, then m∠WXY = 90 (Right Angle Property)
7	90 + (m∠XYZ) = 180	if (m∠WXY) + (m∠XYZ) = 180 and m∠WXY = 90, then 90 + (m∠XYZ) = 180 (Substitution 8)
8	m∠XYZ = 90	if 90 + (m∠XYZ) = 180, then m∠XYZ = 90 (Add Number to Both Sides 2)
9	∠XYZ is a right angle	if m∠XYZ = 90, then ∠XYZ is a right angle (Right Angle Property (Converse))

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