This Instructional Activity is a part of the Lesson 1, Unit 3, Grade 7. This activity builds on the previous one as students plot a different relationship, comparing the length of each square diagonal to its area. Students use the length measurements from the previous activity and use them to calculate the area of the squares. Unlike in the previous activity, this time both the table and the graph show that the relationship between diagonal length and area is not close to being proportional. As a result, the measurement error does not play a role in this activity.