Transitive Property of Equality Variation 2
Angle Symmetry Example 2
Distance Property 2
Distance Property 1
Collinear Then 180
Subtract Both Sides
Add Term to Both Sides 6
Subtract Both Sides 2
Add Term to Both Sides 7
Transitive Property of Equality Variation 1
Vertical Angles
Angle Addition Theorem
Collinear Angles Property 9
Collinear Angles B
Exterior Angle
Exterior Angle B
Collinear Angles Property 10
Collinear Angles Property 3
Collinear Angles Property 3 B
Collinear Angles Property 3 C
alternate interior angles then parallel
ParallelThenAIA
Parallelthenaiashort
Commutative Property Example 2
Commutative Property Variation 1
Substitution 2
Substitution 8
Angle Symmetry B
Substitution Example 10
Substitute First Term
Triangles Sum to 180
Substitute 2
Associative
Add 6 Numbers
Add Associative 2
Rearrange Sum 6
Rearrange Sum 6 2
Reorder Terms 2
Add Term to Both Sides 2
Substitution 6
Simplify Rearrange Sum 6
Swap B And C
Reorder Terms 3
Sum of Angles in Quadrilateral is 360
Multiplicative Identity 2
Distributive Property 4
Multiplicative Property of Equality Variation 1
Addition Theorem
Multiply 2
Divide Both Sides
Multiplicative Property of Equality Variation 2
Transitive Property of Equality Variation 3
Division is Commutative
Associative Property
Divide Each Side
Reorder Terms 6
Reorder Terms 7
Converse of the Supplementary Angles Theorem
Aia Then Parallel 3
Interior Supplementary Then Parallel
If Angles Congruent Then Parallelogram
Add Terms Twice
Add Substitute Term
Add Three
Add Four
Reduce Addition
If Equiangular Then Rectangle

Proof: Vertical Angles

Let's prove the following theorem:

if m∠XPW = 180 and m∠YPZ = 180, then m∠WPZ = m∠XPY

W Y Z X P

Proof:

View as a tree | View dependent proofs | Try proving it

Given
1 m∠XPW = 180
2 m∠YPZ = 180
Proof Table
# Claim Reason
1 (m∠XPY) + (m∠YPW) = 180 if m∠XPW = 180, then (m∠XPY) + (m∠YPW) = 180
2 m∠XPY = 180 + ((m∠YPW) ⋅ (-1)) if (m∠XPY) + (m∠YPW) = 180, then m∠XPY = 180 + ((m∠YPW) ⋅ (-1))
3 (m∠YPW) + (m∠WPZ) = 180 if m∠YPZ = 180, then (m∠YPW) + (m∠WPZ) = 180
4 m∠WPZ = 180 + ((m∠YPW) ⋅ (-1)) if (m∠YPW) + (m∠WPZ) = 180, then m∠WPZ = 180 + ((m∠YPW) ⋅ (-1))
5 m∠WPZ = m∠XPY if m∠WPZ = 180 + ((m∠YPW) ⋅ (-1)) and m∠XPY = 180 + ((m∠YPW) ⋅ (-1)), then m∠WPZ = m∠XPY
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