Area of a circle

using System;
namespace ConsoleApplication3{
    class Program{
        static void Main(string[] args){
            int r;
            Console.Write("Enter the circle's radius: ");
            r = Convert.ToInt32(Console.ReadLine());
            double area = 3.14 * r * r;
            Console.WriteLine("The circle's area is "+area);
            Console.ReadLine();
        }
    }
}