1 #include <bits/stdc++.h>
 2 using namespace std;
 3 typedef long long ll;
 4 inline int read()
 5 {
 6     int x=0,f=1;
 7     char ch=getchar();
 8     while(ch<'0'||ch>'9')
 9     {
10         if(ch=='-')
11             f=-1;
12         ch=getchar();
13     }
14     while(ch>='0'&&ch<='9')
15     {
16         x=x*10+ch-'0';
17         ch=getchar();
18     }
19     return x*f;
20 }
21 inline void write(int x)
22 {
23     if(x<0)
24     {
25         putchar('-');
26         x=-x;
27     }
28     if(x>9)
29     {
30         write(x/10);
31     }
32     putchar(x%10+'0');
33 }
34 const double pi=acos(-1.0);
35 const double eps=1e-9;
36 double r,R,h,H,V;
37 inline double check(double r,double R,double h,double H)
38 {
39     double u=h/H*(R-r)+r;
40     return pi*1.0*(r*r+u*u+u*r)*h/3;
41 }
42 int main()
43 {
44     int n;
45     n=read();
46     while(n--)
47     {
48         scanf("%lf%lf%lf%lf",&r,&R,&H,&V);
49         double L1=0.0;
50         double R1=100.0;
51         double mid;
52         while(L1+eps<R1)
53         {
54             mid=(L1+R1)/2;
55             double vv=check(r,R,mid,H);
56             if(fabs(vv-V)<=eps)
57                 break;
58             else if(vv>V)
59                 R1=mid-eps;
60             else L1=mid+eps;
61         }
62         printf("%.6lf\n",mid);
63     }
64     return 0;
65 }