# Circumference of Circle : How to calculate it easily

Circumference of circle is to be calculated while doing craft work, putting fencing around the yard, or solving a math problem for school. Learning how to find the circumference of a circle will come as a great help in a varied problems related to circle.

There are two methods to calculate the circumference of circle :-

• Using the Diameter

#### Circumference of circle : Using the Diameter

Write down the formula for finding the circumference of a circle using the diameter.

The formula is simply this:

C = ?d

In this equation, “C” represents the circumference of the circle, and “d” represents its diameter. And you can to say, to find the circumference of a circle just multiply the diameter by pi. Plugging ? into the calculator will give you the numerical value, which is a closer approximation of 3.14 or 22/7.

Plug the given value of the diameter into the formula and solve.

Let’s take n example problem: You have a circle pool with a diameter of 16 feet, and you wish to build a white yard wall that creates a 12-foot wide space around the pool. To find the circumference of the wall that has to be created, you must first find the diameter of the wall and the pool which will be 16 feet + 12 feet + 12 feet, which will account for the entire diameter of the pool and wall. The diameter is 16 + 12 + 12, or 40 feet. Now plug it into the formula, plug ? into your calculator for its numerical value, and solve for the circumference:
C = ?d
C = ? x 40
C = 125.6 feet

#### Circumference of circle : Using the Radius

Write down the formula for finding the circumference of a circle using the radius.

The radius is half as long as the diameter, so the diameter can be thought of as 2r. Keeping this in mind, you can write down the formula for finding the circumference given the radius: C = 2?r. In this formula, “r” represents the radius of the circle. Again, you can plug ? into your calculator to get its numeral value, which is a closer approximation of 3.14.

Plug the given radius into the equation and solve.

Let’s say you’re cutting out a decorative strip of paper to wrap around the edge of a pie you’ve just made. The radius of the pie is 10 inches. To find the circumference that you require, just plug the radius into the equation:
C = 2?r
C = 2? x 10
C = 20?
C = 62.4 inches

So, follow any of the above methods to get the circumference.