C# program to calculate circle area

Following program shows you how to calculate circle area.
In this tutorial will get circle radius from user and calculate area and prints it using following formula
Area = PI X r X r

using System;

class MainClass {
  public static void Main (string[] args) {
    Console.WriteLine ("Please enter the radius of circle:");
    double circleRadius = Convert.ToDouble(Console.ReadLine());

    double areaOfCircle = Math.PI * (circleRadius * circleRadius);
    Console.WriteLine("Area of circle is: " + areaOfCircle);

  }
}

Output:

Please enter the radius of circle:
 6
Area of circle is: 113.097335529233