Let's prove the following theorem:

if the following are true:

then a = 90

Given

1	((a + a) + a) + a = 360
2	not (4 = 0)

Proof Table

#	Claim	Reason
1	((a + a) + a) + a = a ⋅ 4	((a + a) + a) + a = a ⋅ 4 (add_four)
2	a ⋅ 4 = 360	if ((a + a) + a) + a = 360 and ((a + a) + a) + a = a ⋅ 4, then a ⋅ 4 = 360 (Transitive Property of Equality Variation 2)
3	a = 360 / 4	if not (4 = 0) and a ⋅ 4 = 360, then a = 360 / 4 (Divide Each Side)
4	360 / 4 = 90	360 / 4 = 90 (Fixed Value Statement)
5	a = 90	if 360 / 4 = 90 and a = 360 / 4, then a = 90 (Transitive Property of Equality)

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