We saw prior to how to discover the perimeter that the polygon. We understand that circle is no a polygon. Therefore, it should not have a perimeter. We use an equivalent form for a circle, called circumference.

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In this article, we will discuss how to find a circle’s circumference, the circumference of a one formula, examples, and also sample problems about the one of a circle.

What is the one of a circle?

The distance about a polygon, such together a square or a rectangle, is referred to as the perimeter (P). Top top the other hand, the distance approximately a one is referred to as the circumference (C). Therefore, the circumference of a one is the linear distance that an edge of the circle.

Why carry out we do should calculate the circumference of a circle?

Finding the circumference of an object is crucial in the following scenarios:

Whether you desire to purchase a bra, trouser, or sweater, you require to know the distance about your belt or chest. Though her body no a perfect circle, friend will need to measure the circumference using a ice cream measure. Tailors mainly use this an approach to recognize the one of a dress.

You also need to know the circumference of a circle act craftwork, placing fencing about your hot tub, or just solving a math trouble for school.

How to find the circumference of a circle?

As declared before, the perimeter or circumference of a one is the distance approximately a circle or any type of circular shape. The one of a one is the exact same as the length of a right line urgent or bent to make the circle. The circumference of a circle is measure in meters, kilometers, yards, inches, etc.

There space two ways of finding the perimeter or circumference of a circle. The first formula involves using the radius, and also the second involves using the diameter the a circle. The is important to keep in mind that both two approaches yield the exact same result.

Let’s take a look.

The circumference the a circle is provided by;

C = 2 * π* R = 2πR


where, D = 2R = The diameter of a circle

For any type of circle, that circumference proportion to the diameter is same to a constant known together pi.

Circumference/Diameter = Pi

C /D = Pi or C/2R = pi

The approximate worth of pi (π) = 22/7 = 3.1415926535897…. (a non-terminating value)

For the much easier computation of a circle’s circumference, pi’s value is taken to be 3.14 (π = 3.14).

Let’s check out a few examples listed below to polish the ide of the circumference.

Example 1

Find the one of the circle with a radius that 8 cm.


Circumference = 2 * π* R = 2πR

= 2 * 3.14 * 8

= 50.24 cm.

Example 2

Calculate the circumference of a circle who diameter is 70 mm


Circumference = π* D = π D

= 3.14 * 70

= 219.8 mm

Example 3

Calculate the perimeter of a one flower garden whose radius is 10 m.


Circumference = 2 * π* R = 2πR

= 2 * 3.14 * 10

= 62.8 m.

Example 4

The one of a one is 440 yards. Discover the diameter and also radius the the circle.


Circumference = 2 * π* R = 2πR

440 =2 * 3.14 * R

440 = 6.28R

Divide both political parties by 6.28 come get,

R = 70.06

Therefore, the radius of the one is 70.06 yards. But, due to the fact that the diameter is twice the radius the a circle, the diameter is equal to 140.12 yards.

Example 5

The diameter of the wheel of a bike is 100 cm. How numerous revolutions will certainly each wheel make to take trip a distance of 157 meters?


Calculate the one of the bicycle’s wheel.

Circumference = π D

= 3.14 * 100

= 314 cm

To acquire the number of revolutions the the wheel, divide the distance covered by the circumference of the wheel.

We require to transform 157 meters to cm prior to dividing, so us multiply 157 through 100 to gain 15700 cm. Therefore,

Number of transformations = 15700 cm/314 cm

= 50 revolutions.

Example 6

A piece of a cable in the kind of a rectangle of size 100 cm and also width 50 centimeter is cut and folded to do a circle. Calculate the circumference and also radius the the circle formed.


The one of the circle formed = the perimeter the the rectangle-shaped wire.

Perimeter of a rectangle = 2(L + W)

= 2(100 + 50) cm

= 2 * 150 cm

= 300 cm.

Therefore, the circumference of the circle will certainly be 300 cm.

Now calculation its radius.

Circumference = 2 π R

300 centimeter = 2 * π * R

300 cm = 2 * 3.14 * R

300 cm = 6.28R

Divide both sides by 6.28.

R = 47.77 cm

So, the radius that the circle will certainly be 47.77 cm.

Example 7

The radius of each wheel that a motorcycle is 0. 85 m. How much will the motorcycle relocate if each wheel bring away 1000 revolutions? i think the motorcycle is moving on a right line.


First, uncover the one of the wheel.

Circumference = 2 π R

= 2 * 3.14 * 0.85

= 5.338 m.

To discover the street traveled, multiply the circumference of the wheel by the number of revolutions taken.

Distance = 5.338 * 1000

= 5338 m

Therefore, the street traveled is equal to 5.338 kilometers.

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Practice Questions

A 12-inch pizza is offered to Mike and also his friends. Mike is interested in calculating the circumference. Assist him!The perimeter of a details square is 1/3rd the area the a particular circle. If the size of the square is L units, determine the circle’s diameter in terms of L.