Re: OT: Converting miles/km

On 2/28/2025 10:29 PM, Tilde wrote:

J. J. Lodder wrote:

Christian Weisgerber <naddy@mips.inka.de> wrote:

On 2024-09-19, Christian Weisgerber <naddy@mips.inka.de> wrote:

Yes, the natural logrithm of 5 approximates the conversion factor
between miles and kilometers; specifically one mile is about ln(5)
kilometers.

PS:

"The Maritime Approximation"
https://xkcd.com/3023/

   pi mph = e knots

Why would a sailor, or a pilot, want to know about miles?

Being born on land a sailor or a pilot would no doubt
become first acquainted with m (or km).

Speculation: The "knot" measuring system and the term "knots" come from
the 16th or 17th Century. I believe, at that time, men heading to sea
were very young; at such tender ages I don't expect very many were
either particularly familiar with any systems of measurements (land or
otherwise) or the arithmetic principles necessary to manipulate the units.

There is of course no need to drag time into it.
It can be simplified to pi landlubber miles
equals e seaman miles,

Cute, but simpler still

pi landlubber miles equals e 1.2*miles--

Jeff Barnett