Area of a circle in C

#include<stdio.h>

#define pi 3.1416

int main()

{

       //Area of a circle = pi r*r

       float          radius, area;

       printf("Enter the radius value :  ");

       scanf("%f ", &radius);

 

       area = pi*radius*radius;

       printf("Area of a circle is: %.2f",area);

       return (0);

}