Radius of circle

using System;

class ProgramReadRadiusOfCircle
{
    static void Main(string[] args)
    {
        Console.WriteLine("Plese enter positive number for circle's radius value =");
        double radius = double.Parse(Console.ReadLine());
        double pi=3.14156926;
        double perimeter = 2 * (pi * radius);
        double area = pi * (Math.Pow(radius, 2));
        Console.WriteLine("The perimeter of the circle is {0}", perimeter);
        Console.WriteLine("The area of the circle is {0}", area);

    }
}