One HUGE problem with the math - distance of Sun and Moon from Earth are not the the same as they were 5,000 years ago. Also throws into question what was the rotation of the Earth at that time.
BTW, the article states that Egyptian pyramid builders went to Britian to study the measurements. Did they go Carnival or Disney? How did they even know about Britain?
Also the conventional story is that Eratosthenes had to use more rudimentary methods to estimate the size of the earth (He made a couple of compensating errors but came up with a remarkably accurate answer). On the other hand he didn’t have to travel all the way to Britain.
Also the Winchester bushel was a cylinder 18.5 inches in diameter and 8 inches high which was rounded to 2150.42 cubic inches.