1. 4.6 Use Isosceles and Equilateral Triangles
Then: You identified isosceles and equilateral triangles. Now: 1. Use properties of isosceles triangles. 2. Use properties of equilateral triangles.

2. Review Classify each triangle by its sides. 1. 2 cm, 2 cm, 2 cm
2. 7 ft, 11 ft, 7 ft
3. 9 m, 8 m, 10 m
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3. Properties of Isosceles Triangles
Use the following vocabulary words to label the triangle: 1. Legs 2. Vertex 3. Base 4. Base angles

4. Theorem 4.10 Isosceles Triangle Theorem
If two sides of a triangle are congruent, then the angles opposite those sides are congruent.
If AB  AC, the  B   C

5. Theorem 4.11 Converse of Isosceles Triangle Theorem
If two angles of a triangle are congruent, then the sides opposite those two angles are congruent.
If B  C, then AB  AC.

6. Example 1:
Complete the statement. Tell what theorem you used. a. If AE  CE, then _____  _____. b. If DAE   DEA, then ______  _____.

7. Corollaries- Equilateral Triangle

8. Example 2: Find missing measures.
a. Find m R. b. Find PR.

9. Example 3: Find missing values.
Find the value of each variable.

10. Example 4: Find the value of x.
a. b.

11. Example 4:
c. Find the values of x and y.

12. Example 5:
Find the values of x and y.

13. 4.6 Assignment:
p #1-22 evens, 29-32, 38-43, , evens