crossed ledder

#include<bits/stdc++.h>
using namespace std;
#define suni ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0)
#define endl "\n"
#define mn int main()
#define frac() cout.unsetf(ios::floatfield);cout.precision(6);cout.setf(ios::fixed,ios::floatfield);
typedef long long ll;
mn
{
    suni;
    int t; cin>>t;
    for(int i=1;i<=t;i++){
        double x,y,c;
        cin>>x>>y>>c;
        double l=0,r=min(x,y);
        for(int i=1;i<=100;i++){
            double d=(l+r)/2.0;
            double h1=sqrt((x*x)-(d*d));
            double h2=sqrt((y*y)-(d*d));
            double h=((h1*h2)/(h1+h2));
            if(h>c) l=d;
            else r=d;
        }
        frac();
        cout<<"Case "<<i<<": "<<l<<endl;
    }
}