Type Casting - Getting Number With Two Decimal Places As Output?

"Type Casting" .... So the question is "How am I getting a number with two decimal places as output?"

import java.util.Scanner;
public class SalesTax
{
public static void main(String[] args) {
double purchase, tax;
Scanner input = new Scanner(System.in);
System.out.print("Enter purchase amount: ");
purchase = input.nextDouble();
tax = purchase * 0.06;
System.out.println("Sales Tax: $" + (int)(tax * 100) / 100.0); +//this will give two decimal places??+
}
}