M3 Proof Properties

Front

If 3x + y = 14 and y = 9, then 3x + 9 = 14.

Back

Substitution Property of Equality: If a = b, then a can be replaced with b in any expression.

Front

If ∠A and ∠B are complementary, then m∠A + m∠B = 90°.

Back

Definition of Complementary Angles: Two angles are complementary if the sum of their measures is 90 degrees.

Front

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

Back

Definition of Midpoint: A point that divides a segment into two equal parts.

Front

∠4 = ∠4

Back

Reflexive Property of Equality: Any quantity is equal to itself.

Front

If a = b, then 8a = 8b.

Back

Multiplication Property of Equality: If you multiply both sides of an equation by the same number, the two sides remain equal.

Front

If m∠C + m∠D = 180°, then ∠C and ∠D are supplementary.

Back

Definition of Supplementary Angles: Two angles are supplementary if the sum of their measures is 180 degrees.

Front

If AB ≅ CD and CD ≅ EF, then AB ≅ EF.

Back

Transitive Property of Equality: If a = b and b = c, then a = c.

Front

If x + 5 = 12, then x = 12 - 5.

Back

Subtraction Property of Equality: If you subtract the same number from both sides of an equation, the two sides remain equal.

Front

If 2x = 10, then x = 10/2.

Back

Division Property of Equality: If you divide both sides of an equation by the same non-zero number, the two sides remain equal.

Front

If ∠A + ∠B = 90° and ∠A = 30°, then ∠B = 60°.

Back

Angle Addition Postulate: If point B lies in the interior of ∠AOC, then m∠AOB + m∠BOC = m∠AOC.