Unfortunately you won't find it anywhere.
I was told it a long time ago, and then look at patterns, base 12 comes up a lot.
base 10 doesn't seem to exist in nature. Except we have 4 fingers and 1 thumb. 4+1

The standard system, although hard to convert, each have a human meaningful measurement.
Like, a foot is the size of your foot.
And if you look at Michaelangelo's depiction of man in a square/circle all these dimensions play out as part of the body and are good units to use for building things for man.