| A | B |
|---|
| *A line segment consists of | both its end points and all the points on the line in between its endpoints |
| *A ray consists of the initial point A and all the points on that line. If a point C lies in between AB, than | than CA and CB are opposite rays |
| *Congruent Complements Theorem: | If two angles are complementary to the same angle or to congruent angles, then they are congruent |
| *Vertical Angles Theorem | If two angles are Vertical angles then they are congruent |
| *If two lines are parallel to the same line, then | then they are parallel to each other. |
| *If two coplanar lines are perpendicular to the same line, then | then they are perpendicular to each other. |
| *If two lines are perpendicular they | they intersect to form two right angles |
| *All right angles are | are congruent |
| *If two lines intersect to form a pair of adjacent, congruent angles, then | then the lines are perpendicular |
| Alternate Interior Angles Theorem | If two parallel lines are cut by a transversal, then the pairs of alternate interior <'s are congruent |
| Consecutive Interior Angles Theorem | If two parallel lines are cut by a transversal, then the pairs of consecutive interior angles are supplementary |
| *Alternate Exterior Angles Theorem | If two parallel lines are cut by a transversal, then the pair of alternate exterior angles re congruent |
| Perpendicular Transversal Theorem: | If a transversal is perpendicular to one of the two parallel lines, then it is perpendicular to the second. |
| *Triangles Sum Theorem | The sum of the interior angles of a triangle is 180 |
| *Third Angles Theorem | If two angles of one triangle are congruent to two angles of a second triangle, then the third angles are also congruent. |
| The acute angles of a right triangle are | are complementary |
| Exterior Angles Theorem: | The measure of exterior angles of a triangle is equal to the sum of the measures of the remote non-adjacent interior angles. |
| Angle-Angle-Side | If two angles and non-included side of one triangle are congruent to two angles and the corresponding non-included side of a second triangle, then the two triangles are congruent. |
| Base angles theorem | If two sides of a triangle are congruent, then the angles opposite them are congruent |
| *Hypotenuse-Leg theorem | If a hypotenuse and the leg of a right triangle are congruent to the hypotenuse and leg of another triangle then the 2 legs are congruent. |
| If one side of a triangle is longer than another side, | then the angle opposite the longer side is larger than the angle opposite the shorter side. |
| If one angle of a triangle is larger than another angle, | then the side opposite the larger angle is longer than the side opposite the smaller angle. |
| The sum of the lengths of any two sides of a triangle is | is greater than the length of the third side |
| Hinge Theorem | If two sides of one triangle are congruent to two sides of another triangle, and the included angle of the first is larger than the included of the second, then the third side of the first is longer than the third side of the second. |
