4 6 Isosceles and Equilateral Triangles Legs of

4. 6 Isosceles and Equilateral Triangles

Legs of an Isosceles Triangle Vertex Angle Base Angles The two _______________ are called ______ of an isosceles triangle. The ______ with the sides that are _________ is called the vertex angle. The ______ of the triangle ________ the vertex angle is called the base. The _______ formed by the base and _____________ are called the base angles.

If two _________ of a triangle are ________, Isosceles Triangle Theorem then the _____ opposite those sides are ___________. If two ________ of a triangle are congruent, then Converse Isosceles Triangle Theorem the sides __________ those angles are congruent.

Example 1 a) Name two unmarked congruent angles. b) Name two unmarked congruent segments.

Example 1 Continued c) Which statement correctly names two congruent angles? a) ÐPJM @ ÐPMJ b) ÐJMK @ ÐJKM c) ÐKJP @ ÐJKP d) ÐPML @ ÐPLK

A triangle is ___________ only if it is Equilateral Triangle _____________. (4. 3) Each _____ of an equilateral triangle measures ____. Equilateral Triangle (4. 4)

Example 2 a) Find mÐR b) Find PR.

Example 3 • You can use the properties of equilateral triangles and algebra to find missing values. • Find the value of each variable.

Summary

Summary

Summary