#include<iostream>

#include<cstdio>

#include<cmath>

#include<algorithm>

#define MN 50000

#define eps 1e-10

using namespace std;

inline int read()

{

    int x =  , f = ; char ch = getchar();

    while(ch < '' || ch > ''){ if(ch == '-') f = -;  ch = getchar();}

    while(ch >= '' && ch <= ''){x = x *  + ch - '';ch = getchar();}

    return x * f;

}

struct P{

    double x,y;

    P(double _x=,double _y=):x(_x),y(_y){}

    P operator + (P b) {return P(x+b.x,y+b.y);}

    P operator - (P b) {return P(x-b.x,y-b.y);}

    P operator * (double b) {return P(x*b,y*b);}

    friend double cross(P a,P b) {return a.x*b.y-b.x*a.y;}

}p[MN+],pt[MN+];

struct L{

    P p,v;double slop;

    L(){}

    L(P x,P y):p(x),v(y){slop=atan2(y.y,y.x);}

    P operator * (L b){P a=p-b.p;double t=cross(b.v,a)/cross(v,b.v);return p+v*t;}

    bool left(P b){ return cross(v,b-p)>eps;}

    bool operator < (const L &y) const {return slop<y.slop;}

}s[MN+],q[MN+];

int n,top,tail;

void solve()

{

    q[top=tail=]=s[];

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

    {

        while(top>tail&&!s[i].left(p[top])) --top;

        while(top>tail&&!s[i].left(p[tail+])) ++tail;

        if(fabs(s[i].slop-q[top].slop)<eps)

            q[top]=s[i].left(q[top].p)?q[top]:s[i];

        else q[++top]=s[i];

        p[top]=q[top]*q[top-];

    }

    while(tail<top&&(q[tail].left(p[top])==)) --top;

}

int main()

{

    for(int T=read();T;T--)

    {

        n=read();

        for(int i=;i<=n;i++) scanf("%lf%lf",&pt[i].x,&pt[i].y);

        for(int i=;i<=n;i++) s[i]=L(pt[i-],pt[i]-pt[i-]);

        s[]=L(pt[n],pt[]-pt[n]);

        sort(s+,s+n+); solve();

        if(top-tail+<)

        {

            for(int i=;i<n;i++) s[i]=L(pt[i+],pt[i]-pt[i+]);

            s[n]=L(pt[],pt[n]-pt[]);

            sort(s+,s+n+);solve();

        }

        if(top-tail+<) puts("0.00");

        else

        {

            p[tail]=q[tail]*q[top];double area=;

            for(int i=tail;i<top;i++) area+=cross(p[i],p[i+]);

            area+=cross(p[top],p[tail]);

            printf("%.2f\n",fabs(area)/2.00+eps);

        }

    }

    return ;

}