This activity will enable the student to discover BOTH equations of a circle. The Nspire activity will show three different interactive circles: the first with only the radius able to be manipulated, the second with only the center and the third with both. While the student works with both the Nspire and a worksheet, he/she will see how the radius changes the equation and then the center and then BOTH.

Download Circle Equations.tns to calculators and handout "Equations of a Circle".

Teachers should offer as little help as necessary with the activity, other than the transfer of the activity to student calculators.

Have each group of partners connect with another group and determine ONE set of equations and then have that group of four connect with another group of four and determine the TWO equations they would like to present to the class as an answer. Then as a class, compare.

Answers for the attached student worksheet are below.