# What is the circumference of a circle, definition | formula?

The circumference of the circle is the perimeter of the distance around the circle. The total distance around the circular surface of the circle often refers to us the circumference. On this page, we will discuss the circumference or the perimeter of a circle in detail.

what is the circumference of a circle?

The perimeter of a circle is called the circumference. In most cases, students will be asked to find the perimeter of the circle. This simply means finding the circumference of the circle. So the circumference and the perimeter are often used interchangeably to test the understanding level of students in finding the circumference of a circle.

How to find the circumference of a circle.

A circumference of a circle can be found by using a tread and placing it around the circular surface of the circle and then taking the tread to note the measurement on the rule. Alternatively, the formula for finding the circumference of a circle is = 2πr or πd, where r is the radius of the circle, π is = 22/7, and d is the diameter of the circle. Now, when the radius of the circle is given, the formula 2πr can be used to find the circumference of the circle. Also, if the diameter of the circle is given the formula πd can be used to find the circumference of the circle. Let’s understand better by working on some examples.

Example 1. Find the circumference of the circle if the radius is 14cm. (Take π = 22/7).

Solution

circumference of a circle is = 2πr, where r = 14cm and the π = 22/7

= 2× 22/7 ×14cm

= 44/7 × 14cm

= 44 × 2cm, (since 14/7 = 2cm),

= 88cm

∴ The circumference of the circle is 88cm.

Example 2. Find the circumference of a circle whose diameter is 28cm.

Solution

Circumference of the circle is = πd, where π = 22/7 and the d = 28.

= (22/7) × 28cm

= 22 × 4cm, (since 28/7 = 4)

= 88cm

∴ circumference of the circle is = 88cm.

Note: diameter of a circle is = r × r = r^{2}. And the radius of the circle is = d/2.