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What field do you work in, and how many digits of pi do you use? (lemmy.world)

submitted 7 months ago by nycki@lemmy.world to c/asklemmy@lemmy.ml

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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?

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[–] captain_aggravated@sh.itjust.works 11 points 7 months ago

As a pilot I can't think of a time I've ever done numbers math with pi. Private pilots are taught to use an E6B flight computer, which is basically a device for accurately drawing and measuring the triangle you're looking to solve instead of doing algebra and arithmetic.

In the wood shop, if I do have to do algebra rather than just drawing a circle with a compass, I'll use 3.14, and I still have to round to the nearest 32nd of an inch.