public class Triangle {

	private Point pA;
	private Point pB;
	private Point pC;

	public Triangle(Point pA, Point pB, Point pC) {
		this.pA = pA;
		this.pB = pB;
		this.pC = pC;
	}

	public double getArea() {
		// Heron, eine wunderschoene und einfache Formel
		double a = pB.getDistanceTo(pC);
		double b = pC.getDistanceTo(pA);
		double c = pA.getDistanceTo(pB);

		double s = getPerimeter() / 2;

		double areaSqr = s * (s - a) * (s - b) * (s - c);

		return Math.sqrt(areaSqr);
	}

	public double getPerimeter() {
		return pA.getDistanceTo(pB) + pB.getDistanceTo(pC) + pC.getDistanceTo(pA);
	}

	public String toString() {
		return "[" + pA + ", " + pB + ", " + pC + "]";
	}
}