LOJ 1137

/*Basic info
Problem :
Date :
Author : Shesher
*/

#include<bits/stdc++.h>

using namespace std;

///Template
#define in1()    freopen("C:\\Users\\SHESHER\\Rest\\Desktop\\MY COMPUTER\\Code\\Template\\input.txt", "r", stdin);
#define out1()   freopen("C:\\Users\\SHESHER\\Rest\\Desktop\\MY COMPUTER\\Code\\Template\\output.txt", "w", stdout);


//Data types
#define lo      long
#define ll      long long
#define llu     unsigned long long

//loop
#define f1(i,x,y)   for(int i=x;i<=y;i++)

//Constants
#define MAX     10000007
#define MOD     10000007
#define PI      acos(-1.0)

//STL
#define vout(v)    for(int i=0;i<v.size();i++){cout<<v[i]; if(i==v.size()-1) cout<<endl; else cout<<" ";}

//Scan
#define sc(x)   scanf("%d", &x)

double a, n, co;

double cs(double r)
{
    double ang=((r*r)+(r*r)-(a*a))/(2*r*r);
    ang=acos(ang);
    // ang=(ang*180)/PI;

    return ang*r;
}

int main()
{
    // in1();
    // out1();
    int t;
    sc(t);
    f1(ti,1,t){
        cin>>a>>n>>co;

        if(n==0){
            printf("Case %d: 0\n", ti);
            continue;
        }

        double s=(1+(n*co))*a;

        // cout<<s<<endl;

        double l=0.0, r=111111.0, mid;

        //while(l<r){
        for(int i=0;i<100;i++){
            mid=(l+r)/2.0;

            double rv=cs(mid);

            // cout<<"MID "<<mid<<" "<<rv<<endl;

            if(rv>s){
                l=mid;
            }
            else{
                r=mid;
            }
        }

        double temp=a/2.0;
        double small=sqrt((mid*mid)-(temp*temp));
        printf("Case %d: %0.10lf\n", ti, mid-small);
    }

    return 0;
}