## How You Can Find The Area Of A Circle

Circles are a very interesting part of the geometry. The**only thing you need**to solve one (to find anything about it) is the

**length of its radius**. This is completely enough to find a circle's area, circumference and diameter. In other words, radius is totally enough to define a circle. After you have it, you can use the following formulas to solve any circle. But firs, let's define some basic things as follows:

C - circumference

r - radius

d - diameter

pi - 3.14159 - mathematical constant

* - the sign for multiplication

### How to find the area

To calculate the area, you have to use the following formula:###
Area = pi * r^{2}

*Example: to find the area of a circle with radius 2 cm., we have to make the following calculation: 2 x 3.14 x 2 x 2 = 12.56 cm*

^{2}.

### How to find the circumference

The circumference of a circle can be calculated with the following formula:### C = 2*pi*r

*Example: if we have a circle with a radius of 2 cm., its circumference is: 2 * 3.14 * 2 = 12.56 cm*

*Please Note*

*The mathmatical constant*is approximately equal to 3.14159. This number has infinite numbers after the coma, so its decimal representation never ends. This is why nobody can calculate exactly the area and the circumference of a circle...

**pi**is