Geometry Ch. 2 Geometric Proofs Vocab

Reflexive Property of Congruence

AB ≅ AB

Symmetric Property of Congruence

If AB ≅ CD, then CD ≅ AB

Transitive Property of Congruence

If AB ≅ CD and CD ≅ EF, then AB ≅ EF

Definition of Congruent Segments

Segments are congruent if and only if their lengths are equal. AB=CD if and only if AB ≅ CD

Midpoint Theorem

If B is the midpoint of AC, then AB ≅ BC

Segment Addition Postulate

AB+BC=AC

Definition of Congruent Angles

∠A ≅ ∠B if and only if m∠A=m∠B

Vertical Angles Theorem

Vertical angles are congruent

Right Angles Theorem

All right angles are congruent

Definition of Right Angle

The measure of a right angle = 90

(Congruent) Complement(s) Theorem

f two angles are both complementary to the same angle, then those two angles are congruent to each other

Definition of Complementary

m∠A+m∠B=90 OR Two angles that form a right angle are complementary

(Congruent) Supplement(s) Theorem

If two angles are both supplementary to the same angle, then those two angles are congruent to each other

Definition of Supplementary

m∠A+m∠B=180 OR Two angles that form a linear pair are supplementary