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