Circles and Polygons

Here is a group of 12 formulas that are often used in mathematics. Note that trapezoids and composite shapes are not included, although these are very important too..

Here is a group of 12 formulas that are often used in mathematics. Note that trapezoids and composite shapes are not included, although these are very important too..

Area of a Circle (animated)
Finding the Area of a Circle Approximating the Area of a Circle using polygons Demonstrating the Circumference of a Circle |

A Challenge: Can You Find the Center of Circle?

(Hint: You can do this with a sheet of paper and a pencil, but you may want to use the Geometer's Sketchpad instead).

(Hint: You can do this with a sheet of paper and a pencil, but you may want to use the Geometer's Sketchpad instead).

Sucessful? Check your ideas with Dr. James Tanton below.