| A | B |
|---|
| Triangle | A figure formed by three segments joining three noncollinear points. |
| Equilateral Triangle | Has three congruent sides |
| Isosceles Triangle | A triangle with at least two congruent sides. |
| Scalene Triangle | Has no congruent sides |
| Acute Triangle | Has three acute angles |
| Equiangular Triangle | Has three congruent angles |
| Obtuse Triangle | Has one obtuse angle |
| Right Triangle | A triangle with one right angle |
| Interior Angles | The side opposite the right angle in a right triangle |
| Exterior Angles | When the sides of a triangle are extended, the angles that are adjacent to the interior angles are exterior angles |
| Corresponding Angles | When two figures are congruent, the angles that are in corresponding positions are congruent. |
| Corresponding Sides | When two figures are congruent, the sides that are in corresponding positions are congruent |
| Corollary | A statement that can be proved easily by using the theorem |
| Congruent Figures | Two geometric figures that have exactly the same size and shape and all pairs of corresponding angles and corresponding sides are congruent |
| Legs | Sides of a right triangle or the congruent sides of an isosceles triangle |
| Hypotenuse | The side opposite the right angle in a right triangle |
| Triangle Sum Theorem | The sum of the measures of the interior angles of a triangle is 180 degrees. |
| Exterior Angle Theorem | measure of an exterior angle of a triangle is equal to the sum of the measures of the two nonadjacent interior angles. |
| Corollary to the Triangle Sum Theorem | The acute angles of a right triangle are complementary. |
| When two geometric figures are congruent, | there is a correspondence |
| Third Angles Theorem | If two angles of one triangle are congruent to two angles of another triangle, then the third angles are also congruent. |
| Side-Side (SSS) Congruence Postulate | If three sides of one triangle are congruent to three sides of a second triangle, then the two triangles are congruent. |
| Side-Angle-Side (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. |
| Polygon Congruence Postulate | Two polygons are congruent if and only if there is a correspondence between their sides and angle such that: Each pair of corresponding angles is congruent; Each pair of corresponding sides is congruent |
| Angle-Side-Angle (ASA) Congurence Postulate | If two angles and the included side in one triangle are congruent to two angles and the included side in another triangle, then the two triangles are congruent |
| Angle-Angle-Side (AAS) Congruence Postulate | If two angles and a nonincluded side of one triangle are congruent to the corresponding angles and nonincluded side of another triangle, then the triangles are congruent. |
| Hypotenuse-Leg (HL) Congruence Theorem | If the hypotenuse and a leg of a right triangle are congruent to the hypotenuse and a leg of another triangle, then the two triangles are congruent. |
| CPCTC | Corresponding parts of congruent triangles are congruent |
| Isosceles Triangle Theorem | If two sides of a triangle are congruent, then the angles opposite those sides are congruent. |
| Converse of the Isosceles Triangle Theorem | If two angles of a triangle are congruent, then the sides opposit those angles are congruent. |
| Legs of an isosceles triangle | The two congruent sides |
| Vertex Angle | The angle opposite the base of an isosceles triangle |
| Base Angles | The angles whose vertices are the endopoints of the base of an isosceles triangle |
| Corollary | An additional theorem that can be easily derived from the original theorem |
| The measure of each equilateral triangle is___________ | 60 degrees |
| The bisector of the vertex angle of an isosceles triangle is the_____________. | perpendicular bisector of the base |
| A diagonal of a parallelogram divides the parallelogram into ____________. | two congruent triangles |
| Opposite sides of a parallelogram are _____________. | congruent |
| Opposite angles of a parallelogram are _____________. | congruent |
| Consecutive angles of a parallelogram are _____________. | supplementary |
| The diagonals of a parallelogram _____________. | bisect each other |
| A rhombus is a _____________. | parallelogram |
| A rectangle is a _____________. | parallelogram |
| The diagonals of a rhombus are_____________. | perpendicular |
| The diagonals of a rectangle are _____________. | congruent |
| The diagonals of a kite are _____________. | perpendicular |
| A square is a _____________ and _____________. | rectangle; rhombus |
| The diagonals of a square are _____________ and are _____________ of each other | congurent; the perpendicular bisector |
| If two pairs of opposite sides of a quadrilateral are congruent, then the quadrilateral is a _____________. | parallelogram |
| If one pair of opposite sides of a quadrilateral are _________ and ______ then the quadrilateral is a parallelogram | parallel; congruent |
| If the diagonals of a quadrilateral bisect each other, then the quadrilateral is a _____________. | parallelogram |
| If one angle of a parallelogram is a right angle, then the parallelogram is a _____________. | rectangle |
| Housebuilder Theorem | If the diagonals of a parallelogram are congruent, then the parallelogram is a rectangle |
| If one pare of adjacent sides of a parallelogram are congruent, then the parallelogram is a _____________. | rhombus |
| If the diagonals of a parallelogram bisect the angles of the parallelogram, then the parallelogram is a _____________. | rhombus |
| If the diagonals of a parallelogram are perpendicular, then the parallelogram is a _____________. | rhombus |
| Triangle Midsegment Theorem | A midsegment of a triangle is parallel to a side of the triangle and has a measure equal to half of the measure of that side |
| Triangle Inequality Theorem | The sum of the lengths of any two sides of a triangle is greater than the length of the third side |
