Area of the circle

Answer 1

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Radius{

public class Circle // declaration of class - I want to find area of circle

{ 
static void Main(string[] args)
{
double r;

double CircleArea;

double pi = 3.14;

Console.WriteLine("Would you like to know the area of a circle?");//intro message

Console.WriteLine("Please enter the radius."); //promt end-user for number 

Console.ReadLine();//reads input from end-user 

r = Convert.ToDouble(Console.ReadLine()); //assings number from end-user to variable r

CircleArea = (3.14 * r * r); //this is the equation for the area of a circle

Console.WriteLine("The area of the circle is" + CircleArea);

}
}
}

Answer 2

PI*r*r
that r is radius of circle and PI is 3.14...
what exactly your problem?