In this lesson, students make connections between tables, equations, and graphs that represent the same proportional relationship. They start with an activity designed to help them see the different ways in which the structure of the graph and the equation are connected (MP7). For example, the coordinates for any point on the graph can be divided to find the constant of proportionality in the equation. Also, the point on the graph gives the constant of proportionality, .

This work prepares students for the next activity where they see two ways to graph a proportional relationship, depending on which quantity goes on which axis. It builds on previous similar work with tables and equations, giving students an opportunity to remember the fact that the constants of proportionality in the two ways are reciprocals.

One of the activities in this lesson works best when each student has access to devices that can run the applet, because students will benefit from seeing the relationship in a dynamic way.