Geometry proofs vocab.

PROOF LIST (LIVE DOCUMENT) TO STUDY

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Bi-Conditional “… if and only if …”
Implies “if… , then…”
Angle
m∠Measure of Angle
Congruent
Parallel
Perpendicular

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Addition Property of EqualityIf a = b, then a + c = b + c
Subtraction Property of EqualityIf a = b, then a – c = b – c
Multiplication Property of EqualityIf a = b, then ac = bc
Division Property of EqualityIf a = b and c ≠ 0, then
Substitution Property of EqualityIf a = b, then a can be substituted for b in any equation or expression.
Distributive Propertya ( bc ) = ab + ac, where a, b, and c, are real numbers
SimplifyCombine like terms
Reflexive Property of Equalitya = a,   AB = AB, m∠ A = m∠ A
Reflexive Property of Congruence ∠ A ≅ ∠ A
Symmetric Property of Equality If a = b, then b = a , If AB = CD, then CD = AB,         If mA = mB, then mB = mA
Symmetric Property of CongruenceIf , thenIf ∠ A ≅ ∠ B, then ∠ B ≅ ∠ A
Transitive Property of Equality If a = b and b = c, then a = c,If AB = CD and CD = EF, then AB = EF,If mA = mB and mB = mC, then mA = mC
Transitive Property of CongruenceIf a = b  and b = c , then a = c.If ∠ A ≅ ∠ B and ∠ B ≅ ∠ C, then ∠ A ≅ ∠ C
Substitution PropertyIf a = b, then a can be substituted for b.

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Definitions

Congruent  - also equal in measure

Angle Bisector  - divides into two ≅ angle

Segment bisector - line, segment or ray that divides a segment at the midpoint

Midpoint – a point that divides a line segment into two ≅ segments

Supplementary angles - two angles that add up to 180˚

Complementary Angles - two angles that add up to 90˚

Linear Pair – pair of angles that are adjacent and supplementary

Right Angle – Angle measures exactly 90˚

Perpendicular - intersects at a right angle, creates a right angle

Vertical Angles - if vertical angles, then they are congruent

Postulates (assumed true without proof)

Segment Addition Postulate – If B is between AC on a line segment, then AB + BC = AC

Angle Addition Postulate – If T is in the interior of ∠ABC, then m∠ABT + m∠TBC = m∠ABC

Right Angle Congruence – all right angles are congruent

Theorems (statements that have been proven)

Congruent Complements Theorem - two angles complementary to the same angle or congruent angles are congruent

Congruent Supplements Theorem - two angles supplementary to the same angle or congruent angles are congruent

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