This is actually old news that has been around since Petrie noticed a pi relationship between the Kings Chamber length and the North wall back in 1883 and contrary to what you may think, proves nothing. My question is: Why are you so insistent on converting the ancient structures comprised of squares and rectangles into circles? Even if you could do so you still need to show the Ancient Egyptians were aware of pi in any form.
You wrote: 20 RC = 500 digits = 31.25 feet the Babylonian value for pi 3.125 and 31.25 x 13.2 inches = 412.5 inches the length of the Kings chamber.
20 RC equals either 20 x 28 = 560 digits, or 20 RC x 24 = 480 digits, not not 500, that is, unless you are harboring a cubit rod divided into 25 digits somewhere for proof?