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by _dain_ 1031 days ago
I wish those medieval people had defined it as 5040 feet, then it would be divisible by 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 15, 16, 18, 20, 21, 24, 28, 30, 35, 36, 40, 42, 45, 48, 56, 60, 63, 70, 72, 80, 84, 90, 105, 112, 120, 126, 140, 144, 168, 180, 210, 240, 252, 280, 315, 336, 360, 420, 504, 560, 630, 720, 840, 1008, 1260, 1680, and 2520.
3 comments
HPsquared 1031 days ago
For reference, 5280 = 2^5 × 3 × 5 × 11

(8 prime factors, 4 distinct)

So 5280 is better if you want to divide by 11, I guess! What a strange thing, how on earth did it end up with a factor of 11 in there...

Edit: it's complicated: https://math.ucr.edu/home/baez/inches.html

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sokoloff 1031 days ago
There are 11 fathoms in a chain, 10 chains in a furlong, and 8 furlongs to a mile.

Going the other way, 2 yards in a fathom and 3 feet in a yard. That accounts for all the factors above.

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Tempest1981 1030 days ago
Is that why we have 90 degrees in a right angle, instead of 100?

90: 2, 3, 5, 6, 9, 10, 15, 18, 30, and 45

100: 2, 4, 5, 10, 20, 25, and 50

If we used grads, it would be a nice even 100,000 meters per grad, vs 111,111.111 per degree.

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chungy 1031 days ago
Connecting 1 mile to 5280 feet happened many centuries after the medieval period. Such precision wasn't really possible nor desired before the 18th century.

To be specific, 5280 feet = 1 mile didn't happen until 1959 and the United States needed higher precision and remove all the fuzziness out of the units. It might be inconvenient on some aspects, but it was also "close enough" to what miles were already established to be.

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_dain_ 1031 days ago
>To be specific, 5280 feet = 1 mile didn't happen until 1959 and the United States needed higher precision and remove all the fuzziness out of the units. It might be inconvenient on some aspects, but it was also "close enough" to what miles were already established to be.

uh what? are you sure you're not mixing that up with the international geophysical year or something? the mile has been 1760 yards since before the US even existed. it's called the imperial system because of the british empire. they couldn't have done the great trigonometrical survey of india without an accurate mile.

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twic 1031 days ago
1959 must be referring to this: https://en.wikipedia.org/wiki/International_yard_and_pound
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