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Third Angle Theorem
If 2 angles of one triangle are congruent to two angles of a second triangle, the third angles of the triangle are congruent.
The centroid of a triangle is located two thirds of the distance from a vertex to the midpoint of the side opposite the vertex on a median
Isosceles Triangle Theorem
If 2 sides of a triangle are congruent, then the angles opposite those sides are congruent
if the measure of the corresponding sides of 2 triangles are proportional, then the triangles are similar
If the measure of 2 sides of a triangle are proportional to the measure of 2 corresponding sides of another triangle, and the included angles are congruent, then the triangles are similar
Triangle Proportionality Theorem
If a line is parallel to one side of a triangle and intersects the other 2 sides in 2 distinct points, then it separates these sides into segments of proportional lengths
Proportional Perimeters Theorem
If 2 triangles are similar, then the perimeters are proportional to measure of corresponding sides
Angle Bisector Theorem
An angle bisector in a triangle separates the opposite side into segments that have the same ratio as the other 2 sides
Diagonals bisect, opposite sides congruent, consecutive angles supplementary, opposite angles congruent, one pair of opposite sides parallel and congruent
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