this post was submitted on 11 Dec 2024
146 points (98.7% liked)

xkcd

9104 readers
223 users here now

A community for a webcomic of romance, sarcasm, math, and language.

founded 2 years ago
MODERATORS
 

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

https://explainxkcd.com/3023/

top 9 comments
sorted by: hot top controversial new old
[–] [email protected] 35 points 1 month 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 1 month ago (1 children)

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

[–] [email protected] 2 points 1 month 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.

[–] matj1 2 points 1 month ago (1 children)
[–] matj1 9 points 1 month ago

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

π miles = e nautical miles

[–] [email protected] 8 points 1 month ago

Thanks, I hate it

[–] marcos 2 points 1 month ago

This is cursed on so many different levels!

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

God french fry filching dammit.