4 2 Constant Rate of Change Essential Question

4. 2 Constant Rate of Change Essential Question: How can you identify and represent proportional relationships?

Page 123 § Complete with a partner § Go over as a class

Proportional Relationship Notes §

Example 1 § Callie earns money by dog sitting. Based on the table, is the relationship between the amount Callie earns and the number of days a proportional relationship?

Number of Days 1 2 3 4 5 Amount Earned ($) 16 32 48 64 80 §

Time (sec) 2 6 3 9 4 Distance (cm) 10 30 15 45 20 Practice Problem §

Your Turn § Page 125 #3 § Coach Practice book page 17

What is an equation ?

Writing an Equation for a Proportional Relationship Notes § Step 1 – Make a table showing the given information § Step 2 - Write the rates. Put the number you want to be 1 in the denominator (x) and the other number in the numerator (y). § Step 3 - Write an equation, first tell what the variables represent

Writing an Equation Example 2 § Two pounds of cashews shown cost $19, and 8 pounds cost $76. Show that the relationship between the number of pounds of cashews and the cost is a proportional relationship. Then write and equation for the relationship. § Step 1 Make a table relating cost in dollars to pounds # of pounds 2 8 Cost ($) 19 76

Example 2 Conitinued §

Number of Cars Number of People 3 18 5 30 6 36 8 48 Practice Problem §

Your Turn § Page 126 #4

Guided Practice § On your own complete pg 126 #1 -4

Independent Practice § Complete pg 127 -128 #1 -15

4. 2 Reteach § Homework