Lesson 3

Now that students have considered the scale from several perspectives, in this lesson they label and choose a scale for empty pairs of axes as part of graphing proportional relationships. In the first activity, students create representations of proportional relationships when given two to start from. For each representation, they identify key features such as the constant of proportionality and relate how they know that each representation is for the same situation. In the second activity, students use the info gap structure. The student with the problem card needs to graph a proportional relationship on an empty pair of axes that includes a specific point. In order to do so, they need to request information about the proportional relationship as well as calculate the specific point. The focus here is on the graphs students create and their decisions on how to scale the axes in an appropriate manner for the situation.

Print and cut up cards from the Info Gap: Proportional Relationships blackline master.  Prepare 1 set of cards for every 2 students. Provide all students with access to straightedges and graph paper.