#include<iostream>
#include<cstdio>
using namespace std;
void main()
{
    int n;
    double x1,x2,x3,y1,y2,y3,a,b,c,k,m,area;
    cin>>n;
    while(n--){
        cin>>x1>>y1;
        cin>>x2>>y2;
        cin>>x3>>y3;
        a=(y2-y1)/((x1-x2)*(x1-x2));
        b=-2*x1*(y2-y1)/((x1-x2)*(x1-x2));
        c=y1-x1*x1*(y2-y1)/((x1-x2)*(x1-x2))+2*x1*x1*(y2-y1)/((x1-x2)*(x1-x2));
        k=(y3-y2)/(x3-x2);
        m=y2-(y3-y2)/(x3-x2)*x2;
        area=(a*x3*x3*x3/3+(b-k)*x3*x3/2+(c-m)*x3)-(a*x2*x2*x2/3+(b-k)*x2*x2/2+(c-m)*x2);
        printf("%.2lf\n",area);
    }
}