1. Warm Up 10.31.11 Week 3 State the number of sides: 1) Equilateral Triangle 2) Rhombus 3) Rectangular Prism

2. Geometry 4.1 Day 1 I will classify triangles by their sides and angles. Triangle A figure formed by three segments joining three noncollinear points.

3. Acute Triangle Equiangular Triangle 3 acute angles 3 congruent angles Right Triangle 1 right angle Obtuse Triangle 1 obtuse angle

4. Equilateral Triangle Isosceles Triangle 3 congruent sides at least 2 congruent sides Scalene Triangle no congruent sides

5. ∆ EFG is acute and... Ex 1 E F G 58 ⁰ 57 ⁰ 65 ⁰ Rule 1 When describing be as specific as possible. scalene.

6. Vertex The points joining the sides. A B C Points A,B, and C are vertices. Adjacent Sides Two sides sharing the same vertex. andare adjacent to ∠B. Opposite Side The non-adjacent side. is opposite to ∠B.

7. Isosceles Triangle Labels The non-leg side.Base The two congruent sides.Leg leg base An isosceles triangle with 3 congruent sides is an equilateral triangle.

8. Right Triangle Labels hypotenuseThe side opposite the right angle. legsSides that form the right angle. hypotenuse leg

9. Triangle Sum Theorem The sum of the measure of the interior angles of a triangle is 180 ⁰. Theorem 4.1 A B C m ∠A + m ∠B + m ∠C = 180⁰

10. Do: 1 Assignment: textbook Page 198, 10 - 32 evens m∠C? A B C 48 ⁰