Proof: Rectangle Right Angles

Let's prove the following theorem:

Proof:

Proof Table

#	Claim	Reason
1	∠WXY is a right angle	if WXYZ is a rectangle, then ∠WXY is a right angle (Rectangle Property)
2	WXYZ is a parallelogram	if WXYZ is a rectangle, then WXYZ is a parallelogram (Rectangle Property)
3	WZ || XY	if WXYZ is a parallelogram, then WZ || XY (Parallelogram Property 3)
4	(m∠ZWX) + (m∠WXY) = 180	if WZ || XY, then (m∠ZWX) + (m∠WXY) = 180 (Consecutive Interior Angles Property)
5	m∠WXY = 90	if ∠WXY is a right angle, then m∠WXY = 90 (Right Angle Property)
6	(m∠ZWX) + 90 = 180	if (m∠ZWX) + (m∠WXY) = 180 and m∠WXY = 90, then (m∠ZWX) + 90 = 180 (Substitution Example 10)
7	m∠ZWX = 90	if (m∠ZWX) + 90 = 180, then m∠ZWX = 90 (Add Number to Both Sides)
8	∠ZWX is a right angle	if m∠ZWX = 90, then ∠ZWX is a right angle (Right Angle Property (Converse))

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