Warm Up

1. Week 7 Warm Up 09.28.11 1) What is the postulate? m∠ADB + m∠BDC = m∠ADC • B • A C • D 2) If∠ 4 and ∠ 5 are a linear pair and ∠ 4 = 79⁰. What is m ∠ 5?

2. Properties of Equality If a = b then a + c = b + c Addition: If a = b then a - c = b - c Subtraction:

3. Properties of Equality If a = b then ac = bc Multiplication: Division: If a = b then a b = c c

4. Properties of Equality If a = bthen b can replace a. Substitution: If a( b +c ) = ab +ac Distributive:

5. Solve and give reasons: Ex 1 55z – 3( 9z + 12 ) = -64 55z – 3( 9z + 12 ) = -64 Given 55z - 27z - 36 = -64 Distributive property 28z - 36 = -64 Simplify Addition property of equality 28z = -28 Division property of equality z = -1

6. Segment Length Properties of equality for Segment length Reflexive: AB = AB IfAB =CD,then CD =AB Symmetric: Transitive: IfAB =CD,and CD =EF,then AB=EF.

7. Angle Measure Properties of equality for angle measure m∠A = m∠A Reflexive: Symmetric: If m∠A=m∠B, thenm∠B=m∠A Transitive: If m∠A=m∠B, andm∠B=m∠C thenm∠A=m∠C

8. Ex 2 m ∠ 1 + m ∠ 2 = 132⁰ 1 2 m ∠ 2 = 105⁰ show that m ∠ 1 = 27⁰ Given m ∠ 1 + m ∠ 2 = 132⁰ Given m ∠ 2 = 105⁰

9. Ex 1 m ∠ 1 + m ∠ 2 = 132⁰ 1 m ∠ 2 = 105⁰ 2 show that m ∠ 1 = 27⁰ Given m ∠ 1 + m ∠ 2 = 132⁰ Given m ∠ 2 = 105⁰

10. Ex 3 m ∠ 1 + m ∠ 2 = 132⁰ 1 m ∠ 2 = 105⁰ 2 show that m ∠ 1 = 27⁰ Given m ∠ 1 + m ∠ 2 = 132⁰ Given m ∠ 2 = 105⁰ m ∠ 1 + 105⁰ = 132⁰ Substitution property of Eq. m ∠ 1 = 27⁰ Subtraction property of Eq.

11. Do: 1 What is the property when 5x + 7y = 58 and x = 27 5x + 7y = 58 given 5( 27 ) + 7y = 58 ? Assignment: Textbook Page 99, 10 - 27 All