#include<bits/stdc++.h>
using namespace std;

 double l,n,c,len;

 double check(double h)
 {
     double s,r,theta,a,b,c;
     a=l*0.5;

     r=(h/2)+((a*a)/(2*h));
     theta=2*(asin(a/r));
     s=r*theta;
     return s;
 }

int main()
{
    int t,cas,i,j,k;
    cin>>t;
    for(cas=1;cas<=t;cas++)
    {
        cin>>l>>n>>c;
        len=(1+n*c)*l;
        double low=0.0,hi=l,mid,x=60;
        while(x--)
        {
            mid=(low+hi)/2;
            if(check(mid)>len)
                hi=mid;
            else
                low=mid;
        }
        printf("Case %d: %lf\n",cas,mid);
    }
    return 0;
}