Here's a bit of hat trivia that may come in handy if you are the million dollar question creator for a TV game show:
Up until approximately the middle of the 20th Century some hat companies in Italy and England used a hat size scale known as PUNTI. Here is how is worked: The size number is determined by dividing the head circumference in inches by pi + 1 (or 4.145). It is thought that originally the system was designed to indicate the crown height of skull-type hats, and simply evolved into this other system. A PUNTI 5½ is equivalent to a US 7¼ or European 58 cm. Judging by hat size tags alone, Borsalino used the system well into the 20th Century. Wilson and Stafford in the UK also used the PUNTI system.