The area

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#include <stdio.h>
#include <math.h>
const double e=1e-3;
double a,h,d;
double fx(double x)
{return a*(x-h)*(x-h)+d;
}
double area(double x1,double y1,double x2,double y2,double x3,double y3)
{double d1,d2,d3,p,s,x4,y4;d1=sqrt((x2-x3)*(x2-x3)+(y2-y3)*(y2-y3));if (d1<e) return 0;d2=sqrt((x1-x3)*(x1-x3)+(y1-y3)*(y1-y3));d3=sqrt((x1-x2)*(x1-x2)+(y1-y2)*(y1-y2));p=(d1+d2+d3)/2;s=sqrt(p*(p-d1)*(p-d2)*(p-d3));x4=(x1+x2)/2; y4=fx(x4);s+=area(x4,y4,x1,y1,x2,y2);x4=(x1+x3)/2; y4=fx(x4);s+=area(x4,y4,x1,y1,x3,y3);return s;
}
int main()
{double x1,y1,x2,y2,x3,y3,s;int n,i;scanf("%d",&n);for (i=0;i<n;i++){scanf("%lf%lf%lf%lf%lf%lf",&x1,&y1,&x2,&y2,&x3,&y3);h=x1; d=y1;a=(y2-d)/(x2-h)/(x2-h);s=area(x1,y1,x2,y2,x3,y3);printf("%.2lf\n",s);}
}