Theorems

9.4 Pythagorean Theorem- A²+B²=C².

2.3 Right Angle Congruence Theorem-All right angles are congruent.

2.6 Verticle Angles Theorem- Verticle Angles are congruent.

3.4 Alternate Interior Angles- If two parallel lines are cut by a transversal, then the pairs of alternate interior angles are congruent.

3.5 Consecutive Interior Angles- If two Parallel lines are cut by a transversal, then the pairs of consecutive interior angles are supplementary.

3.6 Alternate Exterior Angles- If two parallel lines are cut by transversal, then the pairs of alternate exterior angles are congruent.

4.1 Triangle Sum Theorem- The sum of the measures of the interior angles of a triangle is 180^o.

4.3 Third Angles Theorem- If two angles of one triangle are congruent to two angles of another triangle, then the third angles are also congruent.

4.6 Base Angles Theorem- If two sides of a triangle are congruent, then the angles opposite them are congruent.

6.1 Interior Angles of a Quadrilateral- The sum of the measures of the interior angles of a quadrilateral is 360^o.

6.2- If a quadrilateralis a parallelogram, then its opposite sides are congruent.

6.3- If a quadrilateralis a parallelogram, then its opposite sides are congruent.

6.4- If a quadrilateralis a parallelogram, then its consecutive angles are congruent.

6.5- If a quadrilateralis a parallelogram, then its diagonals bisect each other.

6.6- If both pairs of opposite sides of a quadrilateral are congruent, then the quadrilateral is a parallelogram.

6.7- If both pairs of opposite angles of a quadrilateral are congruent, then the quadrilateral is a parallelogram.

6.8- If an angle of a quadrilateral is supplementary to both of its consecutive angles, then the quadrilateral is a parallelogram.

6.9- If the diagonals of a quadrilateral bisect each other, then the quardilateral is a parallelogram.

6.10- If both pairs of opposite sides of a quadrillateral are congruent and parallel, then the quadrilateral is a parallelogram.

8.2 Side-Side-Side Similarity Theorem- If the corresonding sides of two triangles are proportional, then the triangles are similar.

8.3 Side-Angle-Side Similarity Theorem- If an angle of one triangle is congruent to an angle of a second and the lengths of the sides including these angles are proportional, then the triangles are similar.