How can we help?

You can also find more resources in our Help Center.

Angle Sum Theorem

The angles in a triangle sum to 180

Third Angle Theorem

If 2 angles of 1 triangle are congruent to 2 angles of a second triangle then the third angles of the triangles are congruent

Exterior Angle Theorem

measure of the exterior angle is equal to the sum of the remote interior angles

CPCTC

corresponding parts of congruent triangles are congruent

SSS Postulate

if three sides of one triangle are congruent to three sides of a second, the triangles are congruent

ASA Postulate

if two angles and the included side of one triangle are congruent to two angles and the included side of the second, the triangles are congruent

AAS Theorem

if two angles and a non-included side of one triangle are congruent to the corresponding parts of another triangle, then the triangles are congruent

SAS Theorem

If two sides and the included angle of one triangle are equal to two sides and the included angle of another triangle, then the triangles are congruent

Isosceles Triangle Theorem

if 2 sides of a triangle are congruent, then the angles opposite those sides are congruent

Converse of the Isosceles Triangle Theorem

if 2 ∠s of a triangle are congruent, the opposite sides are congruent