Circumference calculation Explained

Understanding what a circumference of a one is and also how to calculation it is crucial as you move to higher level math. In this write-up you will discover the answers to the following questions.

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What is the circumference of a circle?How deserve to you calculate the one of a circle?

What is the one of a circle?

The circumference of a one is the distance about the external of the circle. That is choose the perimeter of various other shapes favor squares. You can think of it as the heat that defines the shape. For shapes made of directly edges this heat is referred to as the perimeter however for one this specifying line is dubbed the circumference.

This diagram shows the circumference of a circle.


There room two various other important ranges on a circle, the radius (r) and the diameter (d). The radius, the diameter, and also the circumference space the three defining aspects of every circle. Provided the radius or diameter and pi you deserve to calculate the circumference. The diameter is the distance from one next of the circle to the other at its widest points. The diameter will constantly pass through the center of the circle. The radius is fifty percent of this distance. You can likewise think the the radius as the distance in between the facility of the circle and also its edge.

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


How deserve to you calculate the circumference of a circle?

If you recognize the diameter or radius of a circle, you deserve to work the end the circumference. To start with, remember the pi is an irrational number written with the price π. π is about equal to 3.14.

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

Circumference of circle = π x Diameter that circle

This is typically written as C = πd. This tells us that the circumference of the one is 3 “and a bit” time as lengthy as the diameter. We can see this top top the graphic below:


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

Example 1

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


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


Example 2

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


We understand 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 lacking length (marked through a ?) ~ above the diagram below:



The lacking length is the circumference. Utilizing the knowledge that the diameter is 4.3m top top the diagram and knowing that C = πd, we deserve to calculate the circumference. V a little thinking we can easily figure the end that, C = π x 4.3m = 13.51m (to 2 decimal places). The absent length is 13.51m.

How to calculation the circumference of the Earth

Have you ever before wondered how big the earth is? Well, utilizing pi it’s possible to occupational out the one of the Earth! researchers have found that the diameter the the planet is 12,742km. Offered this information, what is the one of the Earth? obtain out a piece of record and a calculator and also see if you have the right to work it out on her own.

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Again, we understand that C = πd, and also that the diameter that the earth is 12,742km. Utilizing this information we deserve to calculate the circumference of the planet as C = π x 12,742km = 40,030km.

Formula for the Circumference and also Area the a Circle


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