static void Main(string[] args)
{
var s = new Tamgiac();
var x = s.Nhap();
Console.WriteLine(x.DienTich());
Console.WriteLine(x.ChuVi);
x.InManHinh();
Console.ReadKey();
}
public Tamgiac Nhap()
{
Console.Write("nhap do dai canh 1 ");
int c1 = int.Parse(Console.ReadLine());
Console.Write("nhap do dai canh 2 ");
int c2 = int.Parse(Console.ReadLine());
Console.Write("nhap do dai canh 3 ");
int c3 = int.Parse(Console.ReadLine());
var tG = new Tamgiac(c1, c2, c3);
return(tG);
}