Circumference calculation Explained

Understanding what a circumference of a one is and also how to calculate it is an important as you move to greater level math. In this write-up you will find out the answers come the following questions.

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What is the one of a circle?How can you calculation the one of a circle?

What is the one of a circle?

The circumference the a one is the distance around the outside of the circle. That is favor the perimeter of other shapes choose squares. You have the right to think the it together the line that specifies the shape. For shapes made of straight edges this line is referred to as the perimeter but for circles this specifying line is dubbed the circumference.

This diagram reflects the one of a circle.


There are two various other important distances on a circle, the radius (r) and the diameter (d). The radius, the diameter, and also the circumference room the 3 defining aspects of every circle. Given the radius or diameter and also pi you can calculate the circumference. The diameter is the distance from one side of the circle to the various other at the widest points. The diameter will constantly pass through the center of the circle. The radius is fifty percent of this distance. Girlfriend can additionally think that the radius as the distance between the center of the circle and its edge.

This diagram mirrors the circumference, diameter, center, and radius on a circle.


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

If you understand the diameter or radius that a circle, you can work out the circumference. To begin with, remember that pi is one irrational number written through the price π. π is about equal come 3.14.

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

Circumference of circle = π x Diameter of 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 have the right to see this on the graphic below:


You can likewise work the end the one of a one if you understand its radius. Remember the the diameter is double 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 that circumference?


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


Example 2

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


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

Example 3

Find the missing length (marked through a ?) ~ above the diagram below:



The lacking length is the circumference. Using the understanding that the diameter is 4.3m on the diagram and also knowing that C = πd, we have the right to calculate the circumference. Through a small thinking us can easily figure out that, C = π x 4.3m = 13.51m (to 2 decimal places). The absent length is 13.51m.

How to calculate the circumference of the Earth

Have you ever before wondered how large the earth is? Well, utilizing pi it’s feasible to occupational out the one of the Earth! researchers have discovered that the diameter the the planet is 12,742km. Offered this information, what is the circumference of the Earth? gain out a item of file and a calculator and see if you can work it the end on your own.

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

Formula for the Circumference and Area that a Circle

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