import java.util.*; public class Main { static class Point { double x, y; Point(double a, double b) { x = a; y = b; } } static class Triangle { Point a, b, c; Triangle(Point a, Point b, Point c) { this.a = a; this.b = b; this.c = c; } } static double getArea(Triangle T) { // TODO: 计算三角形T的面积 double x...