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Equilateral Triangle

a triangle with three congruent sides

Isosceles Triangle

A triangle with at least two congruent sides

Scalene Triangle

a triangle with no congruent sides

Acute Triangle

A triangle with three acute angles

Equiangular Triangle

a triangle where all the angle measurements are the same

Right Triangle

a triangle with 1 right angle

Obtuse Triangle

a triangle with 1 obtuse angle

Legs of a right triangle

sides that form the right angle

Hypotenuse

the longest side of a right triangle

legs of an isosceles triangle

In an isosceles triangle, the two congruent sides.

base of an isosceles triangle

in an isosceles triangle, the non-congruent side.

corollary

A statement that follows immediately from a theorem

congruent

same measures

corresponding angles

angles that are in the same position on two different triangles

corresponding sides

sides that are in the same position on two different triangles

base angles

in an isosceles triangle, the angles adjacent to the base

Triangle Sum Theorem

The theorem that states that the measures of the angles in a triangle add up to 180 degrees.

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

SSS

Two triangles are congruent if all 3 sets of corresponding sides are congruent.

SAS

Two triangles are congruent if 2 sets of corresponding sides and their included angles are congruent.

AAS

Two triangles are congruent if 2 sets of corresponding angles and one set on non-included sides are congruent.

ASA

Two triangles are congruent if 2 sets of corresponding angles and their included side are congruent.

CPCTC

If you use a congruence shortcut, (SSS,SAS,ASA,AAS) to show that 2 triangles are congruent, then you can use this to show that any of their corresponding parts are congruent

Base Angles Theorem

if two sides of a triangle are congruent, then the angles opposite them are congruent

Converse of the Base Angles Theorem

If two angles of a triangle are congruent, then the sides opposite them are congruent.

HL

2 right trianles are congruent if their hypotenuses and a set of corresponding legs are congruent.