1. Proportional and Nonproportional Relationships
7th Grade Math
Lesson Objective:
Students will identify proportional and nonproportional relationships.

2. Vocabulary Proportional Nonproportional
Two quantities that have a constant ratio
Example:
Nonproportional
Two quantities that do NOT have a constant ratio
16 = 16
17 ≠ 20

3. Identifying Proportional Relationships - Tables
Kudzu is a vine that grows an average of 7.5 feet every 5 days. Is the number of days of growth proportional to the length of the vine as measured on the last day?
Length
7.5 15
22.5 30
# of Days 5 10 20
Yes

4. Identifying Proportional Relationships - Tables
The Vista Marina rents boats for $25 per hour. In addition to the rental fee, there is a $12 charge for fuel. Is the number of hours you can rent the boat proportional to the total cost?
Total Cost 37 62 87
112
Hours 1 2 3 4 No

5. Identifying Proportional Relationships – Cross Products
Ms. Cochran is planning a year-end pizza party for her students. Ace Pizza offers free delivery and charges $8 for each medium pizza. Is the cost of an order proportional to the number of pizzas ordered?
16 = 16
Yes

6. Identifying Proportional Relationships – Cross Products
Uptown Pizzeria sells medium pizzas for $7 each but charges a $3 delivery fee per order. Is the cost of an order proportional to the number of pizzas ordered?
17 ≠ 20 No