Circumference calculation Explained

Understanding what a circumference of a one is and how to calculation it is crucial as you move to higher level math. In this article you will discover the answers to the adhering to questions.

You are watching: The circumference of a circle is 60π cm. what is the diameter of the circle?

What is the one of a circle?How have the right to you calculation the one of a circle?

What is the one of a circle?

The circumference that a one is the distance approximately the exterior of the circle. It is like the perimeter of other shapes prefer squares. You deserve to think that it as the heat that defines the shape. For shapes made of right edges this line is referred to as the perimeter but for one this specifying line is dubbed the circumference.

This diagram mirrors the one of a circle.


There space two various other important distances on a circle, the radius (r) and the diameter (d). The radius, the diameter, and also the circumference space the 3 defining elements of every circle. Given the radius or diameter and pi you can calculate the circumference. The diameter is the distance from one side of the circle to the various other at that widest points. The diameter will constantly pass v the center of the circle. The radius is half of this distance. Friend can likewise think that the radius together the distance between the facility of the circle and its edge.

This diagram shows the circumference, diameter, center, and also radius ~ above a circle.


How deserve to you calculate the circumference of a circle?

If you recognize the diameter or radius of a circle, you can work out the circumference. To start with, remember that pi is an irrational number written v the price π. π is around equal come 3.14.

The formula for working out the one of a circle is:

Circumference of circle = π x Diameter that circle

This is frequently written together C = πd. This tells united state that the one of the one is 3 “and a bit” times as long as the diameter. We can see this ~ above the graphic below:


You can also work out the circumference of a one if you understand its radius. Remember that the diameter is dual the size of the radius. We already know that C = πd. If r is the radius the the circle, then d = 2r. So, C = 2πr.

Example 1

If a circle has a diameter the 10cm, what is the circumference?


We understand that C = πd. Since the diameter is 10cm, we recognize that C = π x 10cm = 31.42cm (to 2 decimal places).


Example 2

If a circle has a radius the 3m, what is its circumference?


We know that C = 2πr. Because the radius is 3m, we recognize that C = π x 6m = C= 18.84m (to 2 decimal places).

Example 3

Find the absent length (marked with a ?) ~ above the diagram below:



The absent length is the circumference. Utilizing the expertise that the diameter is 4.3m top top the diagram and also knowing that C = πd, we can calculate the circumference. V a small thinking us can easily figure out that, C = π x 4.3m = 13.51m (to 2 decimal places). The missing length is 13.51m.

How to calculation the circumference of the Earth

Have you ever wondered how huge the earth is? Well, utilizing pi it’s possible to work-related out the one of the Earth! scientists have found that the diameter of the planet is 12,742km. Provided this information, what is the circumference of the Earth? gain out a piece of record and a calculator and see if you can work it the end on her own.

See more: Explain Why Roofers Removing Old Asbestos Fibers, Don'T Forget The Basics

Again, we recognize that C = πd, and also that the diameter that the earth is 12,742km. Using this info we can calculate the circumference of the earth as C = π x 12,742km = 40,030km.

Formula because that the Circumference and Area the a Circle

mometrixNeed a circumference calculator? Click the link in our bio! ##pi ##circumference ##math ##mathematics ##mometrix

♬ original sound – Mometrix check Preparation