Did the ancients do decimals I think this an important point.
1st yes they did in the Indus Valley.
Quote 'From The Roots of Ancient India, The Archaeology of Early Indian Civilisation, second edition, revised by Walter Fairservis Jr (1975): … linear measurement was apparently well standardised. Mackay by good fortune found a piece of shell marked in regular fashion and quite clearly intended as a rule. Nine divisions remain, and from circular markings at two places five units apart it would appear that a decimal system was in vogue. Each division is approx 0.264 inches wide, or a five-unit total of 1.32 inches. Thus a foot in the decimal system would be 13.2 inches,
which fit into a widespread system of the ancient world. Similarly, Vats and Wheeler provided evidence that a cubit was also used. Thus both the smaller and larger units of measurement were used in building and presumably to lay out fields. (p 291) '
one common misconception I have found is also a simple such as the slant angle of the Great Pyramid. The angle 51 deg 50 min 24 sec is based on the number 60 and so is written 51.84 degree.
Many think 51.84 is base 100 so their calculation is slightly out. The reason 51.84 is important is when using 22/7 for the approximate for pi it is the closest to to decimal points.
tan 51.84 degree = 1.272600467 and we know this works well with 22/7 but not only that look at the progression.
1.272600467 squared = 1.619511589 (nearly phi 1.618)
1.619511589 squared = 2.2622818951 twice phi
2.622818951 squared = 6.879179252 687 is the base measure for the GP in Saxon feet755.7 imperial feet.
Now look at tan 51.85 again 1.272600457 and call it 1,272.600457 Saxon feet the diagonal of a square find the side of the square 899.8644199 is the radius of a circle of the pyramid laid flat.
900 Saxon feet = 990 imperial feet and we know the Sarsen circle = 99 imperial feet.
You can see the same pyramid numbers in cos 51.84 = 0.617859613 do the same as above 617.859613 diagonal then side = 436.892 is the height of the pyramid in Saxon feet 480.58 imperial feet.
For the architects to have incorporated so much data on mathematics, geometry, astronomy must have meant rooms full of computers to check data. And by computers I mean people just as the British used rooms full of young navel officers to churn through calculations after the Venus transit in order to compute a Sun distance.