| A | B |
|---|
| Third Angle Theorem | If two angles of one triangle are congruent to two angles of a second triangle, then the third angles of the triangles are congruent. |
| Angle Sum Theorem | The sum of the measures of the angles of a triangle is 180. |
| Exterior Angle Theorem | The measure of an exterior angle of a triangle is equal to the sum of the 2 remote interior angles. |
| Right Angle Corollary (4-1) | The acute angles of a right triangle are complementary. |
| SSS | (Side-Side-Side) - If the sides of one triangle are congruent to the sides of a second triangle, then the triangles are congruent. |
| SAS | (Side-Included Angle-Side) - If two sides and the INCLUDED angle of one triangle are congruent to two sides and the INCLUDED angle of another triangle, then the triangles are congruent. |
| ASA | (Angle-Included Side-Angle) - If two angles and the INCLUDED side of one triangle are congruent to two angles and the INCLUDED side of another triangle, then the triangles are congruent. |
| AAS | (Angle-Angle-Side) - If two angles and a NON-INCLUDED side of one triangle are congruent to the CORRESPONDING two angles and side of a second triangle, the two triangles are congruent. |
| Isosceles Triangle Theorem | If two sides of a triangle are congruent, then the angles opposite those sides are congruent. |
| Converse of Isosceles Triangle Theorem | If two angles of a triangle are congruent, then the sides opposite those angles are congruent. |
| Equiangular Corollary (4-3) | A triangle is equilateral if and only if it is equiangular. |
| Equilateral Angles Corollary (4-4) | Each angle of an equilateral triangle measures 60 degrees. |
