Lesson 9: Graphs of Proportional Relationships (Part 2)
1. Which graphs could indicate a proportional relationship? Explain how you decided.
2. On a graph of side length of a square vs. its perimeter, a few points are plotted.
a. Add at least two more ordered pairs to the table and the graph.
b. Is there a proportional relationship between the perimeter and side length? Explain how
you know.
Unit 2: Introduction to Proportional Relationships Lesson 9: Graphs of Proportional Relationships (Part 2)
3. On a graph of the area of a square vs. its perimeter, a few points are plotted.
a. Add some more ordered pairs to the table and graph.
b. Is there a proportional relationship between the area and perimeter of a square? Explain
how you know.
4. There is a proportional relationship between how many months you have had a streaming
movie subscription and how much money you have paid for the subscription. If you have had
the subscription for 6 months, you have paid $47.94. The point (6, 47.94) is shown on the graph
below.
Unit 2: Introduction to Proportional Relationships Lesson 9: Graphs of Proportional Relationships (Part 2)
a. What is the constant of proportionality in this relationship?
b. What is the meaning of the number you found in part a?
c. Add at least three more points to the graph above, and label with their coordinates.
d. Write an equation that shows the relationship between how much the subscription has cost
you and how many months you have had it. Use C for cost and m for number of months.
5. There is a proportional relationship between the volume of a sample of helium in liters and the
mass of that sample in grams. If the mass of a sample is 5 grams, its volume is 28 liters. (5, 28) is
shown on the graph below.
Unit 2: Introduction to Proportional Relationships Lesson 9: Graphs of Proportional Relationships (Part 2)
a. What is the constant of proportionality in this relationship?
b. In this situation, what is the meaning of the number you found in part a?
c. Add at least three more points to the graph above, and label with their coordinates.
d. Write an equation that shows the relationship between the mass of a sample of helium and
its volume. Use m for mass and v for volume.
6. The graphs below show some data from a coffee shop menu. One of the graphs shows cost (in
dollars) vs. drink volume (in ounces), and one of the graphs shows calories vs. drink volume (in
ounces).
__________________ vs volume
Unit 2: Introduction to Proportional Relationships Lesson 9: Graphs of Proportional Relationships (Part 2)
_____________________ vs volume
a. Which graph is which? Give them the correct titles.
b. Which quantities appear to be in a proportional relationship, and how do you know?
c. For the proportional relationship, find the constant of proportionality. What does that
number mean?
Unit 2: Introduction to Proportional Relationships Lesson 9: Graphs of Proportional Relationships (Part 2)