1 #include<iostream>
 2 #include<algorithm>
 3 #include<cstdio>
 4 #include<cstdlib>
 5 #include<cmath>
 6 #include<cstring>
 7 using namespace std;
 8 const double G=9.8;
 9 const int INF=0x3f3f3f3f;
10 const double PI=acos(-1.0);
11 double h,l,v;
12 double js(double mid){
13     double t=l/(v*cos(mid));
14     double H=v*sin(mid)*t-1.0/2*G*t*t+h;
15     return H;
16 }
17 
18 void sanfen(double l,double r){
19     double m,H=0,temp,mm;
20     while(r-l>=1e-10){
21         m=(l+r)/2;
22         mm=(m+r)/2;
23         if(js(m)>=js(mm))H=js(m),r=mm;//不加等号就错了，这个相当于左移，所以加等号； 
24         else l=m;
25     }
26     printf("%.2lf\n",H);
27 }
28 int main(){
29     while(~scanf("%lf%lf%lf",&h,&l,&v),h||l||v){
30         sanfen(0,PI/2.0);
31     }
32     return 0;
33 }