Bill, Bobbie, and Drew present information on a circle. The presentation defines the key points of a circle. The area of a circle is Pi (3.14) x radius x radius. The diameter of a circle is the line drawn from one end to another inside the circle. The radius is the center of the circle to the edge. To find Pi, one simply takes the circumference/diameter. Circumference/diameter will always equal Pi (3.14) no matter the circle's size. The final point is "what makes a circle a circle"? It is a bunch of little points around the center of the circle that are the same length.