This lesson is optional practice for students to work with square roots in a data-visualization context. A common data visualization uses proportionally sized circles on a map. For the circles to be the right size, the area of the circle should be proportional to the data being represented. This means using the square root to find the radius of the appropriate circle. Students make connections between the data they want to represent and the radius of appropriate circles. Students engage in mathematical modeling (MP4) as they choose which data to represent.

One of the activities in this lesson works best when each pair of students has access to a device that can run the applet because students can create their data display without spending time using a ruler and compass to draw precise circles.