This Instructional Activity is a part of the Lesson 7, Unit 3, Grade 7. In this activity, students use a similar process to see that the relationship between the diameter and area of a circle is not proportional. This echoes the earlier exploration comparing the length of a diagonal of a square to the area of the square, which was also not proportional. Each group estimates the area of one smaller circle and one larger circle. After estimating the area of their circles, students graph the class's data on a coordinate plane to notice that the data points curve upward instead of making a straight line through the origin.