Circumference Of A Circle Formula

Circumference Of A Circle Formula: A circle consists of all points in a plane that are a given distance, called the radius, from a given point called the center.

A segment or line can intersect a circle in several ways.

A segment with endpoints that are the center of the circle and a point of the circle is a radius.
A segment with endpoints that lie on the circle is a chord.
A chord that contains the circle’s center is a diameter.

The circumference of a circle is the distance around the circle.

For a circumference of C units and a diameter of d units or a radius of r units,

C = π.d  or  C = 2πr

Example:  Find the circumference of the circle to the nearest hundredth.

Answer:  C = 2πr  ⇒ Circumference formula

⇒ 2π(13)

≈ 81.68  (Use a calculator)

The circumference is about 81.68 centimeters.