Reinforce graphing circles and writing them in function form by matching the smile face in the TI-Navigator activity center. Use vertex form, then solve for y, and play match my graph and draw the happy face.

Make sure students know how to write equations of circle and then discuss how to solve to y and plug into calculator to see the top and bottom half of a circle. Then start smile.act. Inform students that picture is a little distorted because it is in rectanglar dimensions but the radius is assumed to be 7 units.

Move around the room and assists students to help them achieve their goal. They should be allowed to work in pairs.

When the students are finished and have been successful take a screenshot of their calculators as evidence of partcipation. Next have students make a picture on their calculator with circles and again when finished take a screenshot and print and have the student decorate and supply the equations then post around the room for display.