# C Program for Program to find area of a circle

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

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

## C

`#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;` `}` |

**Output:**

Area is 78.550000

**Time Complexity: **O(1)

**Auxiliary Space: **O(1)

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