Classes are in PHP are like classes in JAVA Programming and C++ Programming. In PHP classes variables are declared as var $tax;. The methods are declared like public function __construct() { }. To call a class in PHP use the declaration like $pythag = new Pythag($r, $a); Here the link to the documentation on using classes in PHP http://php.net/manual/en/book.classobj.php Here is a link to the example program of using classes in PHP http://phpsourcecode.kevinsitinfo.info/class/
Youtube video on classes in PHP