The Size of Pizza

Pizza is likely the most important substance ever created.  As such, it is crucial that we have adequate information for our various pizza dealings.  In civilized society a pizza is 16 inches in diameter.  However, one must occasionally deal with the barbarians of the pizza word: Fast food pizza, eg, Pizza Hut, Dominoes, Papa John's.

To begin, they have had the audacity to make pizzas in sizes in less than the scientifically proven optimal size.  However, they add insult to injury by calling these smaller sizes "large".  Since pizza size increases as the square of half the diameter, decreasing the diameter doesn't have an intuitive effect on the actual reduction in pizza.

To help illustrate the atrocity being done here, I've compiled this table of various pizza sizes.  I've included the name Pizza Hut (or the others) call them, as well as their name to rational humans.  Next, is the diameter and the area.  The slices equivalent lets you know how many slices of a normal 16" pizza you would be getting at the other sizes; they likely are all cut into 8 slices.  % of a real pizza is exactly what it sounds like.

Pizza Hut Name	Actual Name	Diameter (in)	Area (in^2)	Slices Equivalent	% of a Real Pizza
Personal	Joke	6	28.3	1.13	14%
Small	?	10	78.5	3.13	39%
Med	Offensively Small	12	113.1	4.50	56%
Large	Small	14	153.9	6.13	77%
X Large	Pizza	16	201.1	8.00	100%
	X Large	18	254.5	10.13	127%
	Wonderful	20	314.2	12.50	156%

Edit:
I've made a calculator to help compare prices across pizza sizes.