#include<stdio.h>  
int main()  
{  
    double x1,x2,x3,y1,y2,y3,a,b,c,k,h,s; 
    int t,i;  
    scanf("%d",&t);  
    while(t--)  
    {  
            scanf("%lf %lf",&x1,&y1);  
            scanf("%lf %lf",&x2,&y2);  
            scanf("%lf %lf",&x3,&y3);  
            a=(y2-y1)/((x2-x1)*(x2-x1));  
            b=-2*a*x1;  
            c=y1-a*x1*x1-b*x1;  
            k=(y2-y3)/(x2-x3);  
            h=y2-k*x2;  
            s=a/3*(x3*x3*x3-x2*x2*x2)+(b-k)/2*(x3*x3-x2*x2)+(c-h)*(x3-x2);  
            printf("%.2lf\n",s);  
    }  
    return 0;  
}