| A | B |
|---|
| Congruent Triangles | All corresponding angles are congruent, and all corresponding sides are congruent. |
| Equilateral Triangle | A triangle with three congruent sides. |
| Triangle | A three-sided polygon. |
| Isosceles Triangle | A triangle with at least two congruent sides. |
| Scalene Triangle | A triangle with no congruent sides. |
| Actue Triangle | A triangle with three acute angles. |
| Equiangular Triangle | An acute triangle with three congruent angles. |
| Right Triangle | A triangle with exactly one right angle. |
| Obtuse Triangle | A triangle with exactly one obtuse angle. |
| Hypotenuse | The side opposite the right angle in a right triangle. |
| Legs | The two congruent sides of an isosceles triangle. |
| Base | The noncongruent side of an isosceles triangle. |
| Triangle Sum Theorem | The sum of the measures of the interior angles of a triangle is 180 degrees. |
| Third Angles Theorem | If two angles of one triangle are congruent to two angles of a second triangle, thenthe third angles are also congruent. |
| Theorem 4.4 | The acute angles of a right triangle are complementary. |
| Exterior Angle Theorem | The measure of an exterior angle of a triangle is equal to the sum of the measures of the two remote (nonadjacent) interior angles. |
| Exterior Angle Inequality | The measure of an exterior angle of a triangle is greater than the meausre of either of the two remote (nonadjacent) interior angles. |
| SSS Congruence Postulate | If three sides of one triangle are congruent to three sides of a second triangle, then the two triangles are congruent. |
| SAS Congruence Postulate | If two sides and the included angle of one triangle are congruent to two sides and the included angle of a second triangle, then the two triangles are congruent. |
| ASA Congruence Postulate | If two angles and the included side of one triangle are congruent to two angles and the included side of a second triangle, then the two triangles are congruent. |
| AAS Congruence Theorem | If two angles and a nonincluded side of one triangle are congruent to two angles and the corresponding nonincluded side of a second triangle, then the two triangles are congruent. |
| CPCTC | Corresponding parts of congruent triangles are congruent. |
| Base Angles Theorem | If two sides of a triangle are congruent, then the angles opposite them are congruent. |
| Congruent | If two angles of a triangle are congruent, then the sides opposite them are ________. |
| Distance | The _________ between two parallel lines is the length of a perpendicular segment between the two lines. |
| HL Congruence Theorem | If the hypotenuse and a leg of a right triangle are congruent to the hypotenuse and leg of a second right triangle, then the two triangles are congruent. |
| Vertex | An angle in a triangle. |
