I found your older GHMB post and website link interesting [home.hiwaay.net]
The ancient Egyptian cubit of 20.625 inches gives an ancient Egyptian foot of 13.75 inches or 1.1458 English feet.
1.1458 / 2 = .5729 -- this is of course very reminiscent of 1/100 of the Radian value of 57.29577951 = 360 / (2 Pi).
I wonder if we are seeing more evidence of geometrical constants (Pi, 2 Pi, 360/(2Pi) = Radian) made into metrological units in feet here. That seems to be something I've seen at least strongly hinted at repeatedly in my own metrological experiments.
That's nice work even if I don't think Jim was using an actual Egyptian Ft. unit here, more like 2/3 of a septenary palm RC cubit reduction than 4/7th. Ft. unit. But still a very interesting resulting unit as you say in Radian parlance. I had a look over of that topic idea last year in this discussion:
What a nifty shortcut route that is.