/****************************************************

     Author : Coolxxx

     Copyright 2017 by Coolxxx. All rights reserved.

     BLOG : http://blog.csdn.net/u010568270

 ****************************************************/

 #include<bits/stdc++.h>

 #pragma comment(linker,"/STACK:1024000000,1024000000")

 #define abs(a) ((a)>0?(a):(-(a)))

 #define lowbit(a) (a&(-a))

 #define sqr(a) ((a)*(a))

 #define mem(a,b) memset(a,b,sizeof(a))

 const double EPS=1e-;

 const int J=;

 const int MOD=;

 const int MAX=0x7f7f7f7f;

 const double PI=3.14159265358979323;

 const int N=;

 using namespace std;

 typedef long long LL;

 double anss;

 LL aans;

 int cas,cass;

 int n,m,lll,ans;

 int e[N][N],f[N][N];

 void floyd()

 {

     int i,j,k;

     for(k=;k<=n;k++)

     {

         for(i=;i<=n;i++)

         {

             if(i==k)continue;

             for(j=;j<=n;j++)

             {

                 if(i==j || k==j)continue;

                 f[i][j]=min(f[i][j],f[i][k]+f[k][j]);

             }

         }

     }

 }

 int main()

 {

     #ifndef ONLINE_JUDGE

 //  freopen("1.txt","r",stdin);

 //  freopen("2.txt","w",stdout);

     #endif

     int i,j,k,l;

     int x,y,z;

     for(scanf("%d",&cass);cass;cass--)

 //  for(scanf("%d",&cas),cass=1;cass<=cas;cass++)

 //  while(~scanf("%s",s))

 //  while(~scanf("%d",&n))

     {

         LL K;

         double D,H,R;

         scanf("%lf%lf%lld%lf",&D,&H,&K,&R);

         double V=sqr(D/)*H;

         double T=V/R/R/R/*;

         LL t=LL(T);

         if(T>t)t++;

         t=t*K;

         printf("%lld\n",t);

     }

     return ;

 }

 /*

 //

 //

 */