Geometry: congruent triangles

Scalene

No congruent sides

Isosceles

Atleast 2 congruent sides

Equilateral

Three congruent sides

Acute

3 acute angles

Right

1 right angle

Obtuse

1 obtuse angle

Interior angles

The original angles of a polygon

Exterior angles

Formed when the sides of a polygon are extended the exterior angles form linear pairs with the interior angles

Triangle Sum Theorem

The sum of the measure of interior angles is 180

Exterior Angle Theorem

The measure of the exterior angle of a triangle is equal to the sum of the measure of two non-adjacent interior angles

Corollary to the Triangle Sum Theory

The acute angles of a right triangle are complementary

Third Angles Theorem

If two sides of one triangle are congruent to two angles of another triangle then the third angles are also congruent

Reflexive prop of congruent triangles

For any triangle ABC, ABC is congruent to ABC

Symmetric Prop of congruent triangles

If ABC is congruent to DEF then DEF is congruent to ABC

Transitive Prop of congruent triangles

If ABC is congruent to DEF NDEF is congruent to JKL, then ABC is congruent to JKL