#include <cstdio>

 #include <cstring>

 #include <cmath>

 #include <algorithm>

 #define maxn 2000

 using namespace std;

 const double pi=acos(-1.0);

 int main()

 {

     double v,a,k;

     scanf("%lf%lf%lf",&v,&a,&k);

     double ans=;

     a=a*pi/;

     while()

     {

         if(v<0.01) break;

         ans+=(*v*cos(a)*v*sin(a))/10.0;

         double ek=0.5*v*v;

         ek=ek/k;

         v=sqrt(ek*2.0);

     }

     printf("%.2lf\n",ans);

     return ;

 }