#include <iostream>#include <cstdio>#include <cstring>#include <algorithm>#include <map>#include <queue>#include <vector>#include <string>#include <cmath>#define Mod (1000000009LL)#define eps (1e-10)#define Maxn 50#define Pi (acos(-1.0))using namespace std;double T[Maxn],S[Maxn],C[Maxn],R[Maxn];double a,b,h,tmp;double x,ans;int N;double t;int n;long long D,H,B,L;double d,l,b1;double m;double x1,x2,y;double f(double x){ return sqrt(1.0+4.0*m*m*x*x);}double Romberg(double a,double b){ h=b-a; tmp=(f(a)+f(b))*h/2.0; T[0]=tmp; for(int i=0;i<N+3;i++) { tmp=0; x=a+h/2.0; while(x<b-eps) { tmp+=f(x); x+=h; } T[i+1]=(T[i]+h*tmp)/2.0; h/=2.0; } for(int i=0;i<N+2;i++) S[i]=(4.0*T[i+1]-T[i])/3.0; for(int i=0;i<N+1;i++) C[i]=(16.0*S[i+1]-S[i])/15.0; for(int i=0;i<N;i++) R[i]=(64.0*C[i+1]-C[i])/63.0; return R[N-1];}int main(){ N=10; int T1; scanf("%d",&T1); int cas=0; while(T1--) { scanf("%lld%lld%lld%lld",&D,&H,&B,&L); n=B/D; if(B%D) n++; d=(double)(D)/(double)(n); l=(double)(L)/(double)(n); b1=(double)(B)/(double)(n); b1/=2.0; for(x1=0.0,x2=(double)(H)/(b1*b1);x1<x2-eps;) { m=(x1+x2)/2.0; y=Romberg(-b1,b1); if(y>l) x2=m; else x1=m; } ans=H-x1*b1*b1; printf("Case %d:n",++cas); printf("%.2fn",ans); if(T1) printf("n"); }return 0;}
