using System;

​

class Circle

{

    public double radius;

    public void printArea(double radius)

    {

        Console.WriteLine("the area of the circle is" + Math.Round((Math.PI * radius * radius), 2));

    }

}

​

public class Program

{

    public static void Main()

    {

        Circle circle1 = new Circle();

        circle1.radius = 8.3;

        circle1.printArea(circle1.radius);

        Circle circle2 = new Circle();

        circle2.radius = 3.5;

        circle2.printArea(circle2,radius);

        Circle circle3 = new Circle();

        circle3.radius = 4.0;

        circle3.printArea(circle3.radius);

        Console.WriteLine("Please write the radius of your circle and hit Enter afterwards: ");

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

        double pi = Math.PI;

        double area = 2 * pi * radius;

        Console.WriteLine("The Perimeter or Circumference (C=2πr) of your circle is: {0:F2}", area);

    }

}

​

​