4.6 Isosceles and Equilateral Triangles

Legs of an Isosceles Triangle 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. Vertex Angle Base Angles

Isosceles Triangle Theorem If two __________________ of a triangle are ________________, then the _________ opposite those sides are _____________________. Converse Isosceles Triangle Theorem If two ________________ of a triangle are congruent, then 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

Equilateral Triangle (4.3) A triangle is _____________________ only if it is _________________________. Equilateral Triangle (4.4) Each _________ of an equilateral triangle measures ________.

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