• Underwaterbob@lemm.ee
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    1 hour ago

    If anyone is curious, I looked it up and The Guinness Book of World Records currently recognizes Rajveer Meena as the world record holder for Pi memorization. He recited 70’000 digits of Pi while blindfolded in about ten hours in 2015. I can’t even begin to understand how someone could actually do that.

  • letsgo@lemm.ee
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    19 hours ago

    During lockdown I had a bit of time on my hands so I memorised all the digits of pi in the right order.

    • Mikrochip@feddit.org
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      22 hours ago

      Gotta say, using 3 just feels like giving up due to laziness, even in 1200BC.

      Also it’s interesting how the Chinese entries basically stop between 1400 and 1949, whereas European names are far more present during this era. Some Japanese ones, too. I wonder how comprehensive this page is.

      • Console_Modder@sh.itjust.works
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        22 hours ago

        Rounding pi to 3 is just the engineering way. It’s close enough to get the job done and then I don’t have to worry about decimal places. However, using pi=3 typically undershoots your calculations, so personally I like to use pi=4

        • Aceticon@lemmy.dbzer0.com
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          21 hours ago

          An error margin of less than 5% (even better, biased in a known direction) is more than good enough for plenty of use cases.

          An error margin of more than 25% on the other hand, is seldom acceptable.

      • finitebanjo@lemmy.world
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        19 hours ago

        AFAIK the Chinese knew that the value between that of the encompassing shape that meets the circle at tangeants to the inscribed shape whose edges meet the same equidistant points gives us the approximation of pi. So did archimedes, and maybe even the babylonians.

        So while a triangle yields about 3 and satisfies the theorem, you could also theoretically draw a 96 gon and 192 gon like Liu Hui for an accuracy of 9x10^5.

        Personally I just memorize 22/7 or use the Leibniz infinite series if I have to.

      • ccunning@lemmy.world
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        22 hours ago

        Sometimes zero decimals is enough precision even in 2025…

        …but also because of laziness…

    • Karyoplasma@discuss.tchncs.de
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      21 hours ago

      Doesn’t have the famous

      ln(640320³ + 744)/√163
      

      for some reason. Accurate to 14 decimal places I believe which is more accurate than what you need for 99.9% of its applications.

        • andros_rex@lemmy.world
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          18 hours ago

          More like you memorize that to show off. There are tons of high schoolers that know pi to dozens of digits, it’s not really exciting. But most high schoolers fundamentally don’t understand logs.

      • moody@lemmings.world
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        21 hours ago

        It’s been said that with 15 decimals, you can calculate the circumference on the observable universe with a precision of the width of an atom.

        • rmuk@feddit.uk
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          20 hours ago

          It’s also been said that with Pi to just four decimal places you can accurately send a spaceship to one of our nearest neighbouring stars and arrive within one kilometre of your intended target.

          In fairness, that was said by me, and I do tend to be full of shit.

        • Karyoplasma@discuss.tchncs.de
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          20 hours ago

          This is an exaggeration.

          The universe’s radius is around 46.5 billion light years (around 4.4 * 10^26 meters), the error introduced of using 15 decimals of pi is around the order of 10^-16. Thus the error of calculating the circumference would be in the order of

          8.8*10^26 * 10^-16 = 8.8*10^10 meters
          
      • SippyCup@feddit.nl
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        18 hours ago

        14 decimal places is more accuracy than you’d ever need.

        Consider the size of what you’re measuring.

        I’m American so you’re getting SAE units, deal with it.

        If we have a radius of 1", the circumference of my object is 6.283185 or so inches around. Maybe it’s 6.283186. the difference between those two numbers is one one hundred thousandths of an inch. About 25 nanometers. Half the size of the smallest bacterium we’ve ever discovered.

        That is with 6 decimal places. With 8 you can measure a circumference with an accuracy to the single atom. Any smaller than that, and you start charging the result by measuring it at all.

    • NιƙƙιDιɱҽʂ@lemmy.world
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      19 hours ago

      If I write them enough and get enough rejection letters, can I then get accepted as the Guinness World Records record holder for most rejections of Guinness World Record records?

  • sp3ctr4l@lemmy.dbzer0.com
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    18 hours ago

    Is there a Guiness world record for classes or categories of individuals with the most rejection letters from the Guiness World Records association?