A response like that pretty much confirms that you have no idea how precession and the radius of the Earth are related.
No I didnt. I said you didnt know how they were related. The reason you dont know how they are related is because they are not related in the first place!
Ok, can you accept the premise that the ancients were aware of, and could measure, the rate of precession?
Supposing they did, what next? (And by rate you mean how long it takes for one complete precessional cycle).
So using that rate, if you move 1/6th of the way around the Earth, the straight line connecting those two points is the same length as is the radius length of the Earth, right?