#include<cstdio>

#include<cstring>

#include<cmath>

int T;

double a,b,c,d,x;

double ans;

int main()

{

    scanf("%d",&T);

    while(T--)

    {

        scanf("%lf%lf%lf%lf%lf",&a,&b,&c,&d,&x);

        double h=sqrt(c*c-x*x*c*c/(a*a));

        double p=x*c/a;

        double tmp=a*d;

        if(x<=h)

        {

            double m=a*a/sqrt(a*a-x*x);

            double s1=m*x/;

            double s2=a*c-m*x;

            double s3=m*x/;

            if(tmp<=s1) ans=sqrt(tmp/s1)*x;

            else if(tmp<=s1+s2) ans=(tmp-s1+m*x)/m;

            else ans=x+h-sqrt((a*c-tmp)/s1)*x;

        }

        else

        {

            double m=c*c/p;

            double s1=m*h/;

            double s2=a*c-m*h;

            double s3=m*h/;

            if(tmp<=s1) ans=sqrt(tmp/s1)*h;

            else if(tmp<=s1+s2) ans=(tmp-s1+m*h)/m;

            else ans=h+x-sqrt((a*c-tmp)/s1)*h;

        }

        printf("%.2lf\n",ans);

    }

    return ;

}