#include<iostream>
#include<string>
#include<cstring>
#include<sstream>
#include<cctype>
#include<string.h>
#include<algorithm>
#include<cmath>
#include<stack>
#include<fstream>
#include<cstdlib>
#include<vector>
#include<map>
#include<utility>
#include<iomanip>
#include<queue>
#define eps 1e-9
#define max(a,b) ((a>b)?a:b)
#define min(a,b) ((a<b)?a:b)
#define pb(a) push_back(a)
#define mp(a,b) make_pair(a,b)
#define pi acos(-1.0)
using namespace std;

int main()
{
int t,kk=1;
double l,lp,n,c,low,high,mid,ans,r,x;
cin>>t;
while(t--)
    {
    cin>>l>>n>>c;
    lp=( (1.0+(n*c)) *l);
    if(fabs(lp-l)<eps) {
                       printf("Case %d: 0\n",kk++);
                       continue;
                       }
    //cout<<l<<" "<<lp<<endl;
    //cout<<pi<<endl;
    low=eps;
    high=pi;
    ans=0.0;
    for(int i=0;i<=100;i++)
        {
        mid=((low+high)/2.0);
        r=(lp/mid);
        ans=sqrt((2.0*r*r)-(2.0*r*r*cos(mid)));
        if(fabs(l-ans)<eps) break;
        if(l+eps<ans) low=mid;
        /*if(l==ans) break;
        if(l<ans) low=mid;*/
        else high=mid;
        }
    //cout<<r<<endl;
    x=r-sqrt( (r*r) - ((l*l)/4.0) );
    printf("Case %d: %.9lf\n",kk++,x+eps);
    }

return 0;
}