using System;

public class Triangle
{
    private readonly Point a;
    private readonly Point b;
    private readonly Point c;

    private double AB => GetLengthOfSide(a, b);
    private double AC => GetLengthOfSide(a, c);
    private double BC => GetLengthOfSide(b, c);

    public Triangle(Point a, Point b, Point c)
    {
        this.a = a;
        this.b = b;
        this.c = c;
    }

    public double GetPerimeter()
    {
        return AB + AC + BC;
    }

    public double GetSquare()
    {
        double p = (AB + BC + AC) / 2;
        return Math.Sqrt(p * (p - AB) * (p - AC) * (p - BC));
    }

    public bool GetAngleBetweenEqualsSides(out double angle)
    {
        if (AB == BC) {
            angle = Math.Asin(AC / (2 * AB * AC * BC / 4 / GetSquare()));
            return true;
        }
        if (AB == AC) {
            angle = Math.Asin(BC / (2 * AB * AC * BC / 4 / GetSquare()));
            return true;
        }
        if (AC == BC) {
            angle = Math.Asin(AB / (2 * AB * AC * BC / 4 / GetSquare()));
            return true;
        }
        angle = -1;
        return false;
    }

    public bool GetHypotenuse(out double hypotenuse)
    {
        if (Math.Sqrt(AB * AB + AC * AC) == BC ) {
            hypotenuse = Math.Sqrt(AB * AB + AC * AC);
            return true;
        }
        if (Math.Sqrt(AB * AB + BC * BC) == AC) {
            hypotenuse = Math.Sqrt(AB * AB + BC * BC);
            return true;
        }
        if (Math.Sqrt(BC * BC + AC * AC) == AB) {
            hypotenuse = Math.Sqrt(BC * BC + AC * AC);
            return true;
        }
        hypotenuse = -1;
        return false;
    }


    private static double GetLengthOfSide(Point first, Point second)
    {
        return Math.Sqrt((first.GetX() - second.GetX()) * (first.GetX() - second.GetX()) +
            (first.GetY() - second.GetY()) * (first.GetY() - second.GetY()));
    }
}