1. Triangle Congruence 4.5 Isosceles and Equilateral Triangles

2. Objectives  Know what base and vertex angles are  Know how to solve for angles in isosceles and equilateral triangles

4. Vertex Angle: ∠ between the ≅ sides Base Angles: ∠ s opposite the ≅ sides Legs: ≅ sides

5. If 2 sides of a ∆ are ≅, then the base ∠ s are ≅

6. equilateral congruent sides congruent angles ∠ s in an equilateral ∆ equal 60 degrees

7. 70 4 60 50 70 60

8. 65 55 60 65

9. 35 65 50

10. If a line bisects the vertex ∠ of a isosceles ∆, then the line is the ⊥ bisector of the base

12. 2x – 9 2x – 9 + 7x = 180 9x – 9 = 180 9x = 189 x = 21

13. 45 m =45 n =15

14. Objectives  Know what base and vertex angles are  Know how to solve for angles in isosceles and equilateral triangles

15. Homework  4.5 Practice