Steelie,
Taking a shot here:
Distance is measured from your feet to wherever the fly lands. Now some of the competitions specify certain equipment so let's limit this to non-competitive casting (actual fishing). You have a 9' rod, 9' leader/tippet and the target is 45 feet from where you stand. If you make a perfectly straight cast you will actually have 27 feet of line beyond your rods tip-top.
Allan