1. 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

2. Section 4-6 Isosceles and Equilateral Triangles

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

4. 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

5. 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

6. Isosceles Triangle Theorems

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

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

9. Find the value of each variable.
Example 2 & 3

10. Find the value of each variable.
Example 2 & 3

11. Find the value of each variable.
Example 2 & 3

12. Equilateral Triangle Theorems

13. Find the value of the variable.
Example 2 & 3

14. Find the value of the variable.
Example 2 & 3

15. Find the value of the variable.
Example 2 & 3

16. p.290 #15 – 22, 29 – 32
Homework