# Lesson 12

Using Graphs to Compare Relationships

Let’s graph more than one relationship on the same grid.

### Problem 1

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

_____________________ vs volume

1. Which graph is which? Give them the correct titles.
2. Which quantities appear to be in a proportional relationship? Explain how you know.
3. For the proportional relationship, find the constant of proportionality. What does that number mean?

### Problem 2

Lin and Andre biked home from school at a steady pace. Lin biked 1.5 km and it took her 5 minutes. Andre biked 2 km and it took him 8 minutes.

1. Draw a graph with two lines that represent the bike rides of Lin and Andre.
2. For each line, highlight the point with coordinates $$(1,k)$$ and find $$k$$.
3. Who was biking faster?

### Problem 3

Match each equation to its graph.

1. $$y = 2x$$
2. $$y = \frac45 x$$
3. $$y = \frac14 x$$
4. $$y = \frac23 x$$
5. $$y = \frac43 x$$
6. $$y = \frac32 x$$