1071The area

#include <iostream>
#include <iomanip>
using namespace std;
int main()
{ int T;
cin>>T;
while(T--)
{double x1,x2,x3,y1,y2,y3;
cin>>x1>>y1>>x2>>y2>>x3>>y3;
double a,b,c,k,m,s1,s2,s;
a=(y2-y1)/(x2*x2-2*x1*x2+x1*x1);
b=(-2)*a*x1;
c=(4*a*y1+b*b)/(4*a);
k=(y3-y2)/(x3-x2);
m=y2-k*x2;
s1=a*x3*x3*x3/3+b*x3*x3/2+c*x3-k*x3*x3/2-m*x3;
s2=a*x2*x2*x2/3+b*x2*x2/2+c*x2-k*x2*x2/2-m*x2;
s=s1-s2;
cout<<setiosflags(ios::fixed)<<setprecision(2)<<s<<endl;
}
return 0;}