7-3.8 Relating Area

This lesson is an alternative to OUR's lesson 7-3.6. In the lessons for this section I have taken a slightly different path. The goal of this lesson is to establish that the relationship between the area and radius of a circle is NOT proportional. Students get some practice calculating area as well as seeing the connection between the graph and the equation. We also do some vertical mathematizing by getting the kids to move from A=1/2Cr which they developed via a geometric model to A=πr². Since the kids at this point don't really have much in the way of algebraic manipulation skills I got at this form of the equation via tables of values and looking for patterns.

By Jeff Holcomb