XPost: alt.usage.english   
   From: jerry.friedman99@gmail.com   
      
   On Thu, 19 Sep 2024 23:12:52 +0000, Christian Weisgerber wrote:   
      
   > I'm sorry, I don't know where to post this.  I'm crossposting to   
   > alt.usage.english, because statute miles as a unit mostly afflict   
   > the English-speaking world.   
   >   
   > So you want to convert between miles and kilometers.  The conversion   
   > factor is... uh...  A 40-year-old calculator book provides a useful   
   > tip:  Unless you're designing a space probe, you can use ln(5).   
   >   
   > WHAT?   
   >   
   > Yes, the natural logrithm of 5 approximates the conversion factor   
   > between miles and kilometers; specifically one mile is about ln(5)   
   > kilometers.  It's accurate to four digits.   
   >   
   > If nothing else, it's faster to type on a calculator.   
   >   
   > I think that's hysterical.   
      
   Hey, that's closer than the golden ratio.   
      
   I only know log(5) = about 1.6 because my graduate adviser   
   suggested I learn log(2) = 0.7, log(3) = 1.1, log(7) = 2, and   
   log(20) = 3.  It was handy for what I was doing.   
      
   --   
   Jerry Friedman   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)