This article says that NASA uses 15 digits after the decimal point, which I’m counting as 16 in total, since that’s how we count significant digits in scientific notation. If you round pi to 3, that’s one significant digit, and if you round it to 1, that’s zero digits.

I know that 22/7 is an extremely good approximation for pi, since it’s written with 3 digits, but is accurate to almost 4 digits. Another good one is √10, which is accurate to a little over 2 digits.

I’ve heard that ‘field engineers’ used to use these approximations to save time when doing math by hand. But what field, exactly? Can anyone give examples of fields that use fewer than 16 digits? In the spirit of something like xkcd: Purity, could you rank different sciences by how many digits of pi they require?

  • Ada@lemmy.blahaj.zoneEnglish
    723·
    6 个月前

    I’m Australian. I normally manage a pie with 5 digits, unless it’s particularly crumbly or runny, in which case I will sometimes use 10!

    • Hegar@kbin.social
      13·
      6 个月前

      I find this comment absolutely hilarious.

      I recognize your profile pic from a comment months back that was also a short, deadpan reinterpretation of the question that I found hilarious. I can’t for the life of me remember what it was of course.

      Thanks for making me laugh!

    • livus@kbin.social
      81·
      6 个月前

      I bet all the Americans reading this are now imagining you eating some gooey dessert like key lime pie or pumpkin pie with your hands.

    • SuckMyWang@lemmy.world
      4·
      6 个月前

      Well you’re honest about being a liar so there’s that I guess. I on the other hand only speaks the truth and I use all the digits of pi, honestly I do.

      • taiyang@lemmy.world
        4·
        6 个月前

        There are two guards: one speaks only the truth and the other only lies. But both know the infinite digits of pi and are underemployed as guards who never get to use that knowledge.

  • maniacal_gaff@lemmy.world
    40·
    6 个月前

    I haven’t typed the digits of pi for probably 20 years because it’s defined as a double precision float in all the programming libraries I use.

  • Thurstylark@lemm.eeEnglish
    34·
    6 个月前

    Ya know, this thread has inspired me. I’m a sound engineer, and find myself yelling “check one two three four” in the michrophone to test it all the time. I’m gonna start reciting the digits of Pi instead, and then as I learn them, I’ll progressively advance how many numbers of Pi that I use in my everyday job :D

    I work at a library, though. I should probably just go with poetry or Douglas Adams or something, but this makes me sound much more impressive

    • Ephera@lemmy.ml
      12·
      6 个月前

      As a computer scientist, same, but it’s called PI.

      It’s the computer that does the thing with the digits, not me. 🙃

      • hallettj@leminal.spaceEnglish
        5·
        6 个月前

        In which case you’re probably using a predefined 64-bit floating point number, which I think is accurate to 15 digits.

        • Ephera@lemmy.ml
          4·
          6 个月前

          Well, you know what’s funny, after writing the comment above, I double-checked what the π constant is called in Rust, as that’s what I’m mostly coding with these days.

          And well, it actually makes you choose. There’s f32::consts::PI and f64::consts::PI. Which I guess, makes sense. If you’re calculating with 32-bit floats, you should be aware that π is going to be less precise.
          So, yeah, I’m a hoax, computer scientists do need to decide between 32-bit and 64-bit.

          In fact, the one time I needed π in Rust, was as a 32-bit float. I built a tiny gravity simulation in a game engine and game engines generally use 32-bit floats…

        • Ephera@lemmy.ml
          5·
          6 个月前

          Yeah, math conventions and programming conventions don’t always align. As in, basically never…

    • FilterItOut@thelemmy.club
      22·
      6 个月前

      What are you talking about? I constantly explain the calculus of the flow rate in the push IV drug I’m giving by going through the (pi)r^2 * h of the syringe, with emphasis on the dh/dy. All my patients love hearing it. They constantly thank me as I finish giving them the dilaudid.

  • tallricefarmer@sopuli.xyz
    20·
    6 个月前

    I am a farmer who has to graft pipe cuts at various angles. i use 3.14159. which is plenty since i am measuring my cuts to the nearest eighth of an inch and i am not sending this ish to the moon.

  • Asidonhopo@lemmy.world
    18·
    6 个月前

    Retail, and to my knowledge among all my coworkers we have used zero digits of pi.

    When I code in C++ I use 15 digits of pi after the decimal point (double float) but I have only rarely coded for money and have never used pi for those work products, so again, zero digits on the clock.

    Ditto for restaurant work, although 2 decimal points would be more than enough if I needed the volume of a cake or other round food.

  • MissJinx@lemmy.world
    14·
    6 个月前

    I’m an auditor. Zero digits is the norm if I have to use Pi there is something VERY wrong

  • ezchili@iusearchlinux.fyi
    13·
    6 个月前

    When I worked on a website with a map on it I used 15

    50000kms is the kind of distances you get going around the earth so to get it down to a millimeter precision from 50k I think 8 or 10 digits required?

    So I just put 15

    • Victor@lemmy.world
      11·
      6 个月前

      As an aside, you don’t need to/shouldn’t pluralize km. It’s just 50,000 km. 👍