19:3

#include<bits/stdc++.h>
#define fraction() cout.unsetf(ios::floatfield);cout.precision(10);cout.setf(ios::fixed,ios::floatfield);
using namespace std;
const double spc=1e-6;
int main()
{
    int t;
    cin>>t;
    for(int tc=1;tc<=t;tc++)
    {
        double ab,ac,bc,ra,ae,de,abc,ade,p1,p2,bdec;
        cin>>ab>>ac>>bc>>ra;
        p1=(ab+ac+bc)/2;
        abc=sqrt(p1*(p1-ab)*(p1-ac)*(p1-bc));
        double l=0,r=ab;
        for(int i=0;i<100;i++)
        {
            double mid=(l+r)/2;
            ae=(mid/ab)*ac;
            de=(mid/ab)*bc;
            p2=(mid+ae+de)/2;
            ade=sqrt(p2*(p2-ae)*(p2-de)*(p2-mid));
            bdec=abc-ade;
            if((ade/bdec)>ra) r=mid;
            else l=mid;

        }
        fraction();
        cout<<"Case "<<tc<<": "<<l<<endl;

    }

}