1. Constant Rates of Change

2. Warm Up

3. To represent a proportional relationship using an equation find the constant of proportionality, k. An equation for proportional relationships is y=kx.

4. Complete the table and write an equation for the proportional relationship. Be sure to tell what each variable represents.
Tickets 3 5 10 18
Cost
$50.25
$83.75

5. Randall earns money fixing computers
Randall earns money fixing computers. Is the relationship between the amount Randall earns and the number of day a proportional relationship? If so, write an equation for the relationship.
Number of Days 1 2 3 4 5
Amount Earned ($)
175
350
525
700
875

6. Two pounds of peaches cost $4. 50, 5 pounds cost $11
Two pounds of peaches cost $4.50, 5 pounds cost $11.25, and 10 pounds costs $ Show that relationship between the number of pounds of peaches is a proportional relationship. Then write an equation for the relationship. Describe the proportional relationship in words.

7. Exit Ticket Craig earns extra money as a lifeguard. He earns $37
Exit Ticket Craig earns extra money as a lifeguard. He earns $37.00 for 4 hours and $64.75 for 7 hours.
Explain how you know whether the relationship between earnings and time is a proportional relationship.
Identify the constant of proportionality and write an equation for the proportional relationship.