Math

Circles and circumference.

Definition

A circle is a set of all points in a plane that are the same distance (radius) from a center point. The circumference is the distance around the circle, calculated using the radius or diameter.

Examples

Real-world.

  • 1 A bicycle wheel with a 14-inch diameter has a circumference of about 44 inches
  • 2 Finding how much fencing is needed to enclose a circular garden
  • 3 Calculating the distance traveled in one revolution of a merry-go-round
Key Fact

C = 2πr = πd; A = πr²

Studied in

1 unit use this concept.