A circle is a basic geometric shape that is used throughout mathematics. A circle is defined as the shape where every point along its perimeter is an equal distance from its center.
Image  Attribute 

Radius The radius is the distance from the center of the circle to any point along the perimeter of the circle. 

Circumference The circumference, denoted with the variable , is the length around the perimeter of the circle. 

Diameter The diameter is the distance between any two points along the perimeter of the circle that passes through the center of the circle. 

Area The area of a circle is the amount of twodimensional space that fits inside the perimeter of the circle. 