1. Use 22/7 Stephens value for the old metre 39.375 I see as a radius for the earth 3937.5 miles (6336.6185 modern meters note 63360inches in mile).
Diameter then 7875 miles x 22/7 = 24750 miles / 360 = 68.75 miles (interesting to note that the number 68.75 is found in the Kings chamber length length 412.5 inches 34.375 imp feet)
The base length of the pyramid 9068.8 inches Petrie 755.7333 imperial and many have tried to extract a value for the Royal cubit from this number. However all base lengths are varying in length greatest being E. 9076.7 and S. 9069.5 ins.
As you may know I have gone with 20.625 inches for a royal cubit for reason it falls easily into the system of measures called both Imperial and Indus. base 756.25 imp feet and 687.5 Indus feet (note 687.5 same number as miles in one degree and also the length of the KC 412.5 ins.
The height of the pyramid then 280 Royal cubits x 25 = 7,000 digits (see the number 7) / 16 = 437.5 indus feet 481.25 imp feet. The height then multiplied by 22/7 gives base 756.25 imperial feet 687.5 indus feet = 11,000 digits (see number 11 22/7).
2. Here for interest is the old Egyptian value for pi 3.160493827 and our aim is to reach the Socket base mean 9125.9 ins.
This can be either some with fractions ala Jacob or simply multiply. We do it with fractions.
Height of pyramid 481.25 feet / 9 = 53.4722222 x 8 = 427.77777 = the side of a square whose area = the area of a circle with diameter 481.25 and using the old Egyptian value for pi 3.16049.
Repeat process 427.77777 / 9 = 47.5308642 x 8 = 380.2469136 = the side of a square whose perimeter = the circumference of a circle 481.25 using Egyptian value 3.16049.
See it easily 380.2469136 x 2 = 760.4938272 the socket base x 12 = 9,125.925926 (our target 9125.9 ins).
From here we can calculator the circumference and a diameter using the Egyptian value for pi. 760.4938272 (7.5 seconds) x 4 = 3,041.975309 (30 seconds) x 2 = 6083.950617 (1 minute now convert to miles)
1.152263374 miles x 60 = 69.13580247 ( 1 degree) x 360 = 24,888.8888 miles circumference for earth.
Using Egyptian value for pi find diameter = 7,875 Stephens value).
I believe we can add old Egyptian value as an approximate for it seems designed to produce an even result and reach the socket base from original height.