It has instance variables nfaces (int) and sidelength (double) it has getters, getnfaces() and getsidelength() it has a constructor that takes an int holding the number of faces and the side length. after input validation, it sets the instance variables. it has an abstract method, getvolume() that returns a float. a tostring() method that returns a string containing the number of faces and the side length. it can have other methods and/or instance variables if you deem them necessary.