#include <iostream>

#include <cstdio>

#include <cstring>

#include <algorithm>

#include <cmath>

using namespace std;

const double eps = 1e-8;

const double PI = acos(-1.0);

const double INF = 1e5;

int sgn(double x)

{

    if(fabs(x) < eps) return 0;

    return x < 0 ? -1:1;

}

struct Point

{

    double x,y;

    Point() {}

    Point(double _x,double _y)

    {

        x = _x,y = _y;

    }

    Point operator -(const Point &b)const

    {

        return Point(x - b.x,y - b.y);

    }

    //叉积

    double operator ^(const Point &b)const

    {

        return x*b.y - y*b.x;

    }

    //点积

    double operator *(const Point &b)const

    {

        return x*b.x + y*b.y;

    }

};

struct Line

{

    Point p,q;

    Line() {};

    Line(Point _p,Point _q)

    {

        p = _p,q = _q;

    }

    //两直线相交求交点

    //第一个值为0表示直线重合，为1表示平行，为2表示相交

    //只有第一个值为2时，交点才有意义

    pair<int,Point> operator &(const Line &b)const

    {

        Point res = p;

        if(sgn((p-q)^(b.p-b.q)) == 0)

        {

            if(sgn((p-b.q)^(b.p-b.q)) == 0)

                return make_pair(0,res);//重合

            else return make_pair(1,res);//平行

        }

        double t = ((p-b.p)^(b.p-b.q))/((p-q)^(b.p-b.q));

        res.x += (q.x-p.x)*t;

        res.y += (q.y-p.y)*t;

        return make_pair(2,res);

    }

};

//*判断线段相交

bool inter(Line l1,Line l2)

{

    return

        max(l1.p.x,l1.q.x) >= min(l2.p.x,l2.q.x) &&

        max(l2.p.x,l2.q.x) >= min(l1.p.x,l1.q.x) &&

        max(l1.p.y,l1.q.y) >= min(l2.p.y,l2.q.y) &&

        max(l2.p.y,l2.q.y) >= min(l1.p.y,l1.q.y) &&

        sgn((l2.p-l1.q)^(l1.p-l1.q))*sgn((l2.q-l1.q)^(l1.p-l1.q)) <= 0 &&

        sgn((l1.p-l2.q)^(l2.p-l2.q))*sgn((l1.q-l2.q)^(l2.p-l2.q)) <= 0;

}

Point pot[105],peg;

double rad;

int main()

{

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

    int t;

    double x1,y1,x2,y2;

    scanf("%d",&t);

    while(t--)

    {

        scanf("%lf%lf%lf%lf",&x1,&y1,&x2,&y2);

        Line L1=Line(Point(x1,y1),Point(x2,y2));

        scanf("%lf%lf%lf%lf",&x1,&y1,&x2,&y2);

        Line L2=Line(Point(x1,y1),Point(x2,y2));

        if(sgn(L1.p.y - L1.q.y)==0 || sgn(L2.p.y - L2.q.y)==0)

        {

            puts("0.00");

            continue;

        }

        if(!inter(L1,L2))

        {

            puts("0.00");

            continue;

        }

        if(sgn(L1.p.y - L1.q.y) < 0) swap(L1.p,L1.q);

        if(sgn(L2.p.y - L2.q.y) < 0) swap(L2.p,L2.q);

        if(inter(Line(L1.p,Point(L1.p.x,INF)),L2))

        {

            puts("0.00");

            continue;

        }

        if(inter(Line(L2.p,Point(L2.p.x,INF)),L1))

        {

            puts("0.00");

            continue;

        }

        pair<int,Point> pr=L1 & L2;

        Point cp=pr.second;

        pr=Line(L1.p,Point(INF,L1.p.y)) & L2;

        double ans=fabs((L1.p-cp)^(pr.second-cp))/2;

        pr=Line(L2.p,Point(INF,L2.p.y)) & L1;

        ans=min(ans,fabs((L2.p-cp)^(pr.second-cp))/2);

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

    }

    return 0;

}