| A | B |
|---|
| Theorem 2-1 Vertical Angles Theorem | Vertical angles are congruent. |
| Theorem 2-2 Congruent Supplements Theorem | If two angles are supplements of the same angle (or of congruent angles), then the two angles are congruent. |
| Theorem 2-3 Congruent Complements Theorem | If two angles are complements of the same angle (or of congruent angles), then the two angles are congruent. |
| Theorem 2-4 About Right Angles | All right angles are congruent. |
| Theorem 2-5 Comparing 2 angles | If two angles are congruent and supplementary, then each is a right angle. |
| Reflexive Property of Congruence | AB congruent to AB. Angle A congruent to angle A |
| Symmetric Property of Congruence | If AB congruent to CD, then CD congruent to AB. If angle A congruent to angle B, then angle B congruent to angle A. If angle A congruent to angle B, then angle B congruent to angle A. |
| Transitive Property of Congruence | If AB congruent to CD and CD congruent to EF, then AB congruent to EF. If angle A congruent to angle B and angle B congruent to angle C, then angle A congruent to angle C. |
| Law of Detachment | If a conditional is true and its hypothesis is true, then its conclusion is true. If p → q is a true statement and p is true, then q is true. |
| Law of Syllogism | If p → q and q → r are true statements, then p → r is a true statement. |
