The formula for finding the area of a circle is radius squared times pi or r2 x 3.14

    

How it works:
When you square the radius of a circle it looks like the figure below. The radius squared fits into the circle three and a little bit more times. Pi is 3.14 which is three and a little bit more.  Remember that the radius of a circle is a measurement from the center of the circle to one point on the circle.  There are an infinite number of radii in a circle.  It is also half the diameter of the circle.  Think of what "radiate" means when trying to remember the definition of radius.  Radiate means to emit from a center point.

                               

The radius squared project we did in class showed us this hands on. Remember you took the diameter of a circle and squared it to actually create a square that perfectly fits around the circle.  Therefore, the diameter of the circle and the length of the side of the square that surrounds it is the same length.  Then you split the side lengths in half to create radius squares.  You then had four radius squares that made up the diameter square.

SO IN A NUTSHELL.....A=3.14 * r2

Click on the link for a video on finding the area of a circle
http://video.about.com/math/How-to-Find-the-Area-of-a-Circle.htm

Blog Post Created by: RR & LP