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?

  • AdaMEnglish
    77•3 months ago

    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
      16•3 months ago

      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!

      • AdaMEnglish
        3•3 months ago

        I’ll be here all year :P

    • livus
      7•3 months ago

      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.

      • BlueÆther
        3•3 months ago

        If it’s anything like the little island off it’s east coast it will be steak and black pepper of a chicken korma pie

        • AdaM
          2•3 months ago

          Steak and black pepper pie, now that’s what I’m talking about!

            • Hegar
              2•3 months ago

              Chilli beef and cheese from a servo or gtfo.

              • BlueÆther
                1•3 months ago

                I often find chilli beef on the dry side, I guess that it would mean that that pie may need only 5 digits and not the full 10 of a juicy steak pie

                • Hegar
                  1•3 months ago

                  With cheese inside its a sloppy mess and often requires the full 10. Though tbh I haven’t lived in Australia for 10 years or eaten meat in 20, so I wouldn’t listen to anything I have to say about pies.

            • livus
              2•3 months ago

              Sacrilege!

              Firstly 1, 500 km away is not coastal (if it was then the UK is an island off the coast of Iceland).

              Secondly if anyone is off anyone else’s coast it’s the west island which is off our coast, not the other way round.