Introduction

C# Program to Calculate Area of Circle. This program is compiled and tested on a Visual Studio 2012..

using System;

namespace TechStudyCSharp
{
    class Program
    {
        static void Main(string[] args)
        {
            double radius, area;                        
            Console.WriteLine("Enter Radius: ");
            radius = Convert.ToDouble( Console.ReadLine());
            area = Math.PI * radius * radius;
            Console.WriteLine("\nArea of circle: "+area);          
            Console.ReadKey();
        }
    }
}

Result