The circumference is actually the length of the circular line. It is calculated by multiplying the radius by 2, which has an approximate value of π. It can also be said that the circumference is equal to the the diameter of the circumference multiplied by π (since the diameter is actually twice the radius of the circumference). It is customary to identify the circumference (the perimeter) with the letter P.

### The formula for calculating the circumference is:

**$P=2\times\pi\times R$**

**We will illustrate the concept with a simple example. Here is a circle, as shown in the drawing in front of you:**

The radius of the circumference is $3\text{ cm}$.

**You can calculate the circumference of the circle by placing the data:**

$P=2\times R\timesπ=2\times3\times3.14=18.84$

That is, the circumference is $18.84\text{ cm}$.