Geometry 4.1-4.6

HL

Isosceles Triangle Theorem

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

Converse of Isosceles Theorem

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

Triangle Angle Sum

angle 1 + angle 2 + angle 3 = 180

Exterior Angle Theorem

angle 3 = angle 1 + angle 2

3rd Angle Theorem

if angle 1 is congruent to angle 4 and angle 2 is congruent to angle 5, then angle 3 is congruent to angle 6

Side Side Side (SSS)

Side Angle Side (SAS)

Angle Side Angle (ASA)

Angle Angle Side (AAS)

CPCTC

corresponding parts of congruent triangles are congruent