| A | B |
| ReflexiveProperty | For every number a, a = a. |
| SymmetricProperty | For all numbers a & b, if a = b, then b = a.(ex. the segment GH = segment HG) |
| TransitiveProperty | For all numbers a, b & c, if a = b & b = c, then a = c. (A bit like the law of syllogism) |
| Add/Subtract Property | For all numbers a, b, & c, if a = b, then a + c = b + c and a - c = b - c.(ex. 1 ft = 12 inches, 1 ft + 3 inches = 12 in ches+ 3 inches) |
| Mult/Division Property | For all numbers a, b, and c, if a = b, then a * c = b * c, and if c not equal to zero, a ÷ c = b ÷ c.(ex. 1 m = 1000 mm, 1 m * 5 = 1000 mm * 5, 5 m = 5000 mm) |
| SubstitutionProperty | For all numbers a & b, if a = b, then a may be replaced by b in any equation or expression. |
| DistributiveProperty | For all numbers a, b, & c, a(b + c) = ab + ac. |
| THEOREM 2-1 Segment Properties | Congruence of segments is reflexive, symmetric, and transitive. |
| Theorem 2-2 Supplement Theorem | If two angles form a linear pair,then they are supplementary angles. |
| Theorem 2-3 Angle Properties | Congruence of angles is reflexive, symmetric, and transitive. |
| Theorem 2-4 supplementary congruent | Angles supplementary to the same angle or to congruent angles are congruent. |
| Theorem 2-5complementary congruent | Angles complementary to the same angle or to congruent angles are congruent. |
| Theorem 2-6 right congruent | All right angles are congruent. |
| Theorem 2-7 vertical angles | Vertical angles are congruent. |
| Theorem 2-8 perpendicular lines form | Perpendicular lines intersect to form four right angles.. |