程序代码：

#include<iostream>
#include<cmath>
using namespace std;
#define N 9.8
int main()
{
    double h,l,v,res;
    while(scanf("%lf%lf%lf",&h,&l,&v)&&h)
    {
        double x = 2*N*l/(v*v);
        res = asin(x)/2;
        printf("%.2lf\n",v*v*sin(res)*sin(res)/(2*N));
    }
    return 0;
}