1. WARM UP 1.What is an Acute Triangle? 2.What is an Obtuse Triangle? 3.What is a Right Triangle? 4.What is a Scalene Triangle? 5.What is an Isosceles Triangle? 6.What is an Equilateral Triangle? 7.Can an Equilateral Triangle also be an Acute Triangle?

2. http://www.phschool.com/atschool/acade my123/html/bbapplet_wl-problem- 431617.html

3. 3.7 Angle-Side Theorems Theorem 20: If two sides of a triangle are congruent, the angles opposite the sides are congruent. IF Then

4. Theorem 21: If two angles of a triangle are congruent, the sides opposite the angles are congruent. If Then

5. These are ways to prove an isosceles triangle: 1.Two sides are congruent 2.Two angles are congruent Markings on a triangle: Smaller side matches opposite < Medium side opposite med < Larger side opposite larger <

6. T. If two sides are not congruent, then the angles opposite are not congruent. T. If two angles of a triangle are not congruent, their opposite sides are not congruent.

7. Equilateral and Equiangular are interchangeable in triangles. Not in all shapes! Rhombus: equilateral but not equiangular

8. Rectangle: equiangular but not equilateral.

9. 6x-4515+x Given:AC>AB m<B + m<C <180 m<B = 6x – 45 m<C = 15 + x What are the restrictions on the values of x? A BC

10. m m<C m<B + m<C <180 You must solve two unknowns.