Area of a circle can simply be evaluated using following formula.

Area = pi * r^{2}where r is radius of circle

`#include <math.h> ` `#include <stdio.h> ` `#define PI 3.142 ` ` ` `double` `findArea(` `int` `r) ` `{ ` ` ` `return` `PI * ` `pow` `(r, 2); ` `} ` ` ` `int` `main() ` `{ ` ` ` `printf` `(` `"Area is %f"` `, findArea(5)); ` ` ` `return` `0; ` `} ` |

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**Output:**

Area is 78.550000

Please refer complete article on Program to find area of a circle for more details!

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