using System;

public class Triangle

{ protected int a, b, c, p;

 public Triangle(int a, int b, int c, int p)

 { this.a = a; this.b = b; this.c = c;  this.p = p; }

 public Triangle (int a, int b, int c)

 {  this.a = a; this.b = a;  this.c = c;}

  public virtual double Area()

  { return (p * (p - a) * ( p - b) * (p - c)); }

}

 class Triangle

 {  public double Area(int a, int h, int b, double angle)

   { return a*b*Math.Sin(angle)/2;}

  {  return a * h / 2; }

  public double Area(int a, int b, int c, int R)

    { return a*b*c/ (double) (4*R); }

​

​

​