using System;

​

public class Program

{

    public static void Main()

    {

        double at, la, lb, lc, ls;

        Console.Write("Ingrese Longitud A: ");

        la = double.Parse(Console.ReadLine());

        Console.Write("Ingrese Longitud B: ");

        lb = double.Parse(Console.ReadLine());

        Console.Write("Ingrese Longitud C: ");

        lc = double.Parse(Console.ReadLine());

​

        ls = (la + lb + lc) / 2;

        at = (ls * (ls - la) * (ls - lb) * (ls - lc));

        at = Math.Pow(at,.5);

        Console.Write("Area del triangulo: {0}", at);

    }

}