1. Week 3 Warm Up 11.01.11 State the number of sides: 1) Trapezoid
2) Parallelogram
Add theorem 2.1 here next year.

2. m∠x? 58 + 65 + x = 180º 123 + x = 180 x = 180 - 123 x = 57º Re 1 B 65⁰A B C
58⁰ x⁰
65⁰
x = 180º
Add theorem 2.1 here next year.
123 + x = 180
x =
x = 57º

3. I will classify triangles by their sides and angles.
Geometry
4.1 Day 2
I will classify triangles by their sides and angles.
Interior Angles
The three original angles on the inside of the triangle.

4. Exterior Angles
Adjacent to the interior angles.

5. Exterior Angle Theorem
The measure of an exterior angle of a triangle is equal to the sum of the measure of the two nonadjacent interior angles. A B C 1
m∠1 = m∠A + m∠B

6. Ex 1 2x + 10 ( 2x + 10 )º = xº + 65º 2x + 10 = x + 65 2( 55 ) + 10A B C
( 2x + 10 )⁰ x⁰
65⁰
Ex 1
2x + 10
( 2x + 10 )º = xº + 65º
2x = x + 65
2( 55 ) + 10
2x - x = 65
x = 65
120º
x =
x = 55

7. The sum of the measure of the interior angles of a triangle is 180⁰.
Theorem 4.1
Triangle Sum Theorem
The sum of the measure of the interior angles of a triangle is 180⁰.
Don’t Write! A B C
m∠A + m∠B + m∠C = 180⁰.

8. Corollary to the Triangle Sum Theorem
Theorem 4.1B
Corollary to the Triangle Sum Theorem
The acute angles of a right triangle are complementary. A C B
m∠A + m∠B = 90º

9. 2x⁰
Ex 2 x⁰
90º = xº + 2xº
90 = 3x
15 = x

10. P( -2, -3 ) m = y = mx + b -3 = ( ) ( -2 ) + b -3 = 7 + b -3 - 7 = + b
Algebra Review
y = mx + b
Writing Equations
-3 = ( ) ( -2 ) + b
-3 = 7 + b
= + b
-10 = + b
y = x - 10

11. what is the measure of the exterior angle? Do: 1B C
( 10x + 9 )⁰
( 7x + 1 )⁰
38⁰
Add theorem 2.1 here next year.
Assignment:
Textbook Page 198, evens.