static void Main(string[] args)
{
Triangle tr = new Triangle(1, 2, 3);
Console.WriteLine("Let triangle sides be: " + tr.ChangeA + ", " + tr.ChangeB + "," + tr.ChangeC);
Console.WriteLine("Angle between side a and b in this triangle is " + tr.CalculateAngleBetweenAAndB());
Console.WriteLine("Perimeter of triangle with sides " + tr.ChangeA + ", " + tr.ChangeB + ", " + tr.ChangeC + " is " + tr.Perimeter());
Console.WriteLine("Let now change value of a = " + tr.ChangeA + " into a = 2");
tr.ChangeA = 2;
Console.WriteLine("Now angle between side a and b in this triangle is " + tr.CalculateAngleBetweenAAndB());
Console.WriteLine("Now perimeter of triangle is " + tr.Perimeter());
EquilateralTriangle et = new EquilateralTriangle(3);
Console.WriteLine("Area of the equilateral triangle with side = " + et.ChangeA + " is " + et.CalculateArea());
}
