Geometry - Congruent Triangles - Chapter 4

The congruent sides of an isosceles triangle are called ______________.

The non congruent side of an isosceles triangle is called the _______________.

The two angles at the base of an isosceles triangle are called the _________________.

If two angles at the base of an isosceles triangle  congruent, then _______________________.

If two angles of a triangle are congruent, then ________________________________.

If a triangle is equilateral, then it is __________.

If a triangle is equiangular, then it is ____________ .

Theorem 4-1

The Isosceles Triangle Theorem

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

The Isosceles Triangle Theorem (Theorem 4-1) often stated that the base angles of an isosceles triangle are congruent.

*  An equilateral triangle is also equiangular.
*  An equilateral triangle has three 60° angles.
*  The bisector of the vertex angles of an isosceles triangle is perpendicular to the base at its midpoint.

Theorem 4-2

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

Corollary 
An equiangular triangle is also equilateral.

SSS - side, side, side

ASA

SAS

AAS

HL

Find interior and exterior angle sum

Find each interior and exterior angle in regular polygons

Find missing interior and exterior angles in irregular polygons

Differentiate between convex and non-convex polygons

CPCTC