Light OJ 1137

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

typedef long long int           ll;
typedef unsigned long long int  ull;
typedef vector<int>             vi;
typedef vector<vi>              vvi;
typedef pair<int,int>           pii;
typedef vector< pii >           vpii;
typedef set<int>                sti;

#define pb                      push_back
#define pob                     pop_back
#define mp                      make_pair
#define ff                      first
#define ss                      second
#define loop1(i,n)              for(int i=1; i<=int(n); i++)
#define loop(i,y)               for(int i=0; i<int(y); i++)
#define rloop(i,y)              for(int i=int(y)-1; i>=0; i--)
#define read()                  freopen("input.txt", "r", stdin)
#define write()                 freopen("output.txt", "w", stdout)
#define cspf(i)                 printf("Case %d: ", i)
/// Constants
#define eps                     1e-9
#define PI                      acos(-1.0)  // 3.1415926535897932

int main()
{
    int t;
    cin>>t;
    loop1(i,t){
        double l,c,k;
        cin>>l>>c>>k;
        double s=l*(1+c*k);
        double hi,lo,mid,angle,r,rto,ts,b;
        c=l/2;
        hi=c;
        lo=0;
        int g=60;
        while(g--){
            mid=(hi+lo)/2;
            b=mid;
            r=((c*c)+(b*b))/(2*b);
            angle=2*asin(c/r);
            ts=r*angle;
            rto=ts/s;
            if(ts>s)
                hi=mid;
            else
                lo=mid;
        }
        cspf(i);
        printf("%lf\n",b);
    }
    return 0;
}