If ∠1 ≅ ∠2, ∠K ≅ ∠M, and KL ≅ ML , then which statements about the triangle are true? KP ≅ PM PM ≅ NM KP ≅ NM ∠KLP ≅ ∠MLN ∠KLP ≅ ∠PLN ∠PLN ≅ ∠MLN Problem of the Day

Section 4-6 Isosceles and Equilateral Triangles

Then Now Objectives You identified isosceles and equilateral triangles. Use properties of isosceles triangles. Use properties of equilateral triangles.

Common Core State Standards Content Standards G.CO.10 – Prove theorems about triangles. G.CO.12 – Make formal geometric constructions with a variety of tools and methods. Mathematical Practices 2) Reason abstractly and quantitatively. 3) Construct viable arguments and critique the reasoning of others. Common Core State Standards

The two congruent sides are called the legs of an isosceles triangle, and the angle with sides that are the legs is called the vertex angle. The side of the triangle opposite vertex angle is called the base. The two angles formed by the base and the congruent sides are called the base angles. Vocabulary

Isosceles Triangle Theorems

Example 1 Name two unmarked congruent angles. Name two unmarked congruent segments. Example 1

Example 1 Name two unmarked congruent angles. Name two unmarked congruent segments. Example 1

Find the value of each variable. Example 2 & 3

Find the value of each variable. Example 2 & 3

Find the value of each variable. Example 2 & 3

Equilateral Triangle Theorems

Find the value of the variable. Example 2 & 3

Find the value of the variable. Example 2 & 3

Find the value of the variable. Example 2 & 3

p.290 #15 – 22, 29 – 32 Homework