Area of an equilateral triangle

//Area of an equilateral triangle
#include<stdio.h>
#include<math.h>
int main(){
    double side,area;
    printf("Enter side of the equilateral triangle: \n");
    scanf("%lf",&side);
    area=(sqrt(3)/4)*(side*side);//area of an equilateral triangle=(sqrt(3)/4)*(s*s)
    printf("Area of equilateral triangle  = %.2lf sq. units",area);
    return 0;
}