Find radius of circle program in c#.net

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

namespace ConsoleApplication1

{

    class Program

    {

        static void Main(string[] args)

        {

            Double r;

            Double area;

            area = 10.0;

            Console.Write("Enter Area of Circle : ");

            area = Convert.ToDouble(Console.ReadLine());

            r = Math.Sqrt(area / 3.1416);

            Console.WriteLine("Radius is " + r);

            Console.ReadLine();

        }

    }

}