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

submitted 8 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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[–] noughtnaut@lemmy.world 6 points 8 months ago* (last edited 8 months ago) (2 children)

Yes, it's technically correct (which we all know is the best kind of correct) and engineers would understand.

Using mm means most everyone (who knows metric) understands that in much more practical terms. A quarter of a tenth of thiiis much is a pretty damn tight fit.

[–] towerful@programming.dev 5 points 8 months ago

Micrometers is actually so common that it has a colloquial non-SI name of "micron"

According to wiki:

The micrometre is a common unit of measurement for wavelengths of infrared radiation as well as sizes of biological cells and bacteria,[1] and for grading wool by the diameter of the fibres.[3] The width of a single human hair ranges from approximately 20 to 200 μm.

[–] taladar@sh.itjust.works -3 points 8 months ago (1 children)

Bold of you to assume that anywhere close to everyone who understands metric would know that 0.25 is a quarter of something.

[–] TheRaven@lemmy.ca -1 points 8 months ago (1 children)

Bold of you to assume that the country that still uses the Imperial system is the one that better understands fractions.

https://www.cbc.ca/radio/undertheinfluence/how-failing-at-fractions-saved-the-quarter-pounder-1.5979468

[–] taladar@sh.itjust.works -1 points 8 months ago

I didn't say that imperial countries understand them better.