#include<bits/stdc++.h>
using namespace std;
double r,h;
double x0,yy,z0;
double vx,vy,vz;
double a,b,c;
bool check(double t){
double x=x0+vx*t;
double y=yy+vy*t;
double z=z0+vz*t;
if(z>=0&&z<=h&&(x*x+y*y<=r*r)) return 1;
return 0;
}
int main(){
int T;scanf("%d",&T);
for(int cas=1;cas<=T;cas++){
scanf("%lf%lf",&r,&h);
scanf("%lf%lf%lf",&x0,&yy,&z0);
scanf("%lf%lf%lf",&vx,&vy,&vz);
a=h*h*vx*vx+h*h*vy*vy-r*r*vz*vz;
b=2*x0*vx*h*h+2*h*h*yy*vy-2*r*r*z0*vz+2*r*r*h*vz;
c=x0*x0*h*h+yy*yy*h*h-h*h*r*r-z0*z0*r*r+2*h*r*r*z0;
double t1=(sqrt(b*b-4*a*c)-b)/(2*a);
double t2=-1*(sqrt(b*b-4*a*c)+b)/(2*a);
double ans=1e18;
if(check(t1)) ans=min(ans,t1);
if(check(t2)) ans=min(ans,t2);
printf("Case %d: %.10lf\n",cas,ans);
}
return 0;
}
