import java.io.BufferedInputStream;

import java.util.Scanner;

public class Main {

    public static void main(String[] args) {

        Scanner scan = new Scanner(new BufferedInputStream(System.in));

        int n = scan.nextInt();

        while(n--!=0){

            double x1 = scan.nextDouble();

            double y1 = scan.nextDouble();

            double x2 = scan.nextDouble();

            double y2 = scan.nextDouble();

            double x3 = scan.nextDouble();

            double y3 = scan.nextDouble();

            double a = ((y2-y1)*(x3-x2)/(x2-x1)-(y3-y2))/((x2*x2-x1*x1)*(x3-x2)/(x2-x1)-(x3*x3-x2*x2));

            double b = ((y2-y1)-a*(x2*x2-x1*x1))/(x2-x1);

            double c = y1-a*x1*x1-b*x1;

            double s = (a/3*x3*x3*x3+b/2*x3*x3+c*x3)-(a/3*x2*x2*x2+b*x2*x2/2+c*x2)-(y3+y2)*(x3-x2)/2;

            System.out.printf("%.2f",s);

            System.out.println();

        }

        scan.close();

    }

}