Actually there is an intersting mathematical basis to the 65cm rod as opposed to the 7 unit 70cm 4/3 royal cubit...

Quote

Elke Roik has claimed that the nbj was a linear measure equal to 65 cm, which was divided dyadically into eight units

with the setjat area = to 1/800th square mille passus
with the english acre = 1/640th mile and originating from the mille passus.

square root (57600^2 / 640) = 2276.839915 inch side (100 * Phi-0.5 remen royal cubits)
square root (57600^2 / 800) = 2036.467529 inch side (100 remen royal cubits)

square root 800 = 28.284271 (fingers per remen cubit or inches per 4/3rd cubit
sqaure root 640 = 25.298221

2276.839915 / 25.298221 = 90 per side (360 perimeter)
2036.467529 / 28.284271 = 72 per side (288 perimeter)
of course all you have to do is multiply the follwoing foot measure by 5 and add the 1 part....
288 / 25 = 11.520 (root roman - John Neal)
288 / 24 = 12.000 (root greek/english - John Neal)
288 / 21 = 13.714 (root royal egyptian - John Neal)
288 / 20 = 14.4
...but then again 5 x 288 is of course 1 roman Actus quadrans of 1440 inch.

28.571428 (greater)
28.284271 (mean)
28 (lesser)

25.6 (greater) = 650.240mm (Egyptian Artists rod [www.legon.demon.co.uk] )
25.298221 (mean) = 642.575mm (Royal persian cubit [www.touregypt.net] )
25 (lesser) = sacred cubit

256 is of course 2^8 so 1/8th divisions would be quite logical.

28.571428 / 25.6 = 125:112
28.284271 / 25.298221 = v1.25 = Phi -0.5 = 1/Phi +0.5
28 / 25 = royal cubit : common cubit