this post was submitted on 11 Dec 2024
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xkcd

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It works because a nautical mile is based on a degree of latitude, and the Earth (e) is a circle.

https://explainxkcd.com/3023/

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[–] [email protected] 1 points 1 week ago

God french fry filching dammit.

[–] [email protected] 2 points 2 weeks ago

This is cursed on so many different levels!

[–] [email protected] 9 points 2 weeks ago

Knot is just nautical mile per hour, so it can be simplified so:

π miles = e nautical miles

[–] [email protected] 8 points 2 weeks ago

Thanks, I hate it

[–] [email protected] 34 points 2 weeks ago (2 children)

Obligatory repeat of the fact that the ratio between miles and kilometres is ln(5), correct to less than 0.01% (yes, that's a percent of a percent).

The golden ratio or Fibonacci numbers are used more often for the same trick but they're off by, at best, very slightly worse than 0.5%.

[–] [email protected] 7 points 2 weeks ago (1 children)

Fibonacci numbers are easier than ln(5) to calculate on the spot tho

[–] [email protected] 2 points 2 weeks ago

You're not wrong. The ln(5) trick is for when you have a scientific calculator but it doesn't have the conversion built in.

[–] [email protected] 2 points 2 weeks ago (1 children)