#include <bits/stdc++.h>

using namespace std;

long double area(long double x1, long double y1, long double x2, long double y2, long double x3, long double y3)
{
    long double res;
    res = x1*(y2-y3) + x2*(y3-y1) + x3*(y1-y2);
    res = fabs(res);
    res = res*0.5;
    return res;
}
int main()
{
    int t;
    long double x1,y1,x2,y2,x3,y3,x4,y4,cost;
    cin >> t;
    for ( int l = 1; l <= t; l++ ) {
        cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3 >> x4 >> y4 >> cost;
        long double ans = area(x1,y1,x2,y2,x3,y3) + area(x1,y1,x3,y3,x4,y4);
        ans = cost/ans;
        cout << "Case #" << l << ": " << setprecision(2) << fixed << ans << endl;
    }
    return 0;
}