another "cannot find symbol" error :(

i'm new to programming, and i'm currently trying to make a program that can calculate the area of a pentagon...

right now i'm debugging the code online, since i do not have a program installed on this computer. Anyways, i get this error on line 17...can anybody tell me how to fix it and what it is?

AreaPentagon.java:17: cannot find symbol symbol : variable dataIn location: class AreaPentagon side = dataIn.readLine(); ^ 1 error

import javax.swing.JOptionPane;

publicclass AreaPentagon

{

publicstaticvoid main(String[] args)

{

//declare and construct variables

double side;

double pentagonArea;

double strSide;

//print promts and get input

System.out.println("Area of a Regular Pentagon");

System.out.println("What is the length of a side on the Pentagon");

side = dataIn.readLine();

//calculations

pentagonArea = 1.720477 * Math.pow(side,2);

//output

System.out.print("The Area is: " + pentagonArea);

}

}

[1648 byte] By [jvhuggarda] at [2007-11-27 8:12:17]