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

int main()
{
    int t, i;
    double a, b,c,r;
    scanf("%d", &t);
    double  theta;
    for(i=1;i<=t;i++)
    {
        scanf("%lf %lf %lf", &a, &b, &c);

        double s = a+b*c*a;
        //if(s>a*2.0)s=a*2.0;

        double l=0;
        double h=a*a;
        for(int j=0;j<100;j++){
                r=(l+h)/2.0;
        theta = s/r;
       //printf("%lf %lf %lf \n",theta,l,h);
        double f=2*r*sin(theta/2);
        if(f>a){
            h=r;
        }
        else
            l=r;

        }
        double fi=r-r*cos(theta/2);
        printf("Case %d: %.10lf\n", i,fi );

    }
    return 0;
}