• Thunderwolf@lemmy.world
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    5 months ago

    There are people that think this post is wrong because the equation is wrong or due to a lack of units

    The equation for cylindrical volume is correct (circular area multipled by height).

    And the units are unimportant (can be described as cubed units)

    The issue is that Pi is a constant. Constants and variables are different things.

    Other examples of constants: 1, 24, 7, -1 … Etc.

    Saying Pi = 5 is like saying 1 = 5 … Both Pi and numbers like 1,2,3, etc. have a constant (non-varying) value.

    You can’t reassign a value on a constant. It’s like me sticking up 3 fingers and claiming there are 5 fingers there.

    • CameronDev@programming.dev
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      5 months ago

      For the purpose of teaching young school kids how to substitute real values for constants/variables, does it matter? π is a constant, but the value you use for it in exams and real life will not be the same, or the actual correct value. Getting students used to the idea that even constants can have varying values in exams or software is useful.

      In my exams π had values ranging from 3, 3.1 to whatever the calculator had. g also ranged from 9.8 to 10, although in fairness g is not a constant.

      At least setting it to 5 can spark debate around what a more reasonable approximation should be.

      • new_guy@lemmy.world
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        5 months ago

        OP’s problem isn’t even wrong.

        It’s just assuming that π is 5 in this specific scenario, just like it’s reasonable to assume the existence of a spherical cow in a frictionless environment. Yeah, if you use the results of this problem to develop a real cylinder you’re going to have a bad time but nobody is doing that all what’s the problem?

        Nobody is saying that from this point in time and going forward π = 5 and now math is broken forever. People need to chill

    • MinekPo1@lemmy.ml
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      5 months ago

      minor nitpick but the value of π is technically a parameter of the space you are operating in . which means it can have any arbitrary value as long as you are willing to operate in non euclidean spaces (and the space we live in is not euclidean though not to a measurable extent unless you are near a black hole)

      but yeah in this context saying π is a constant is as correct as saying you cant take a square root out of a negative number .

      edit : possibly better example is that a triangle’s angles sum to 180°

  • fckreddit@lemmy.ml
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    5 months ago

    Ancient Greek Mathematicians would be so disappointed. Even they knew that pi is between 3.1 and 3.2.

  • Omega_Haxors@lemmy.ml
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    5 months ago

    POV your state just mandated by law that engineers round pi to the nearest integer (this has happened a few times, but it never sticks)

  • jordanlund@lemmy.world
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    5 months ago

    Well, with those numbers, it’s easy math. :)

    V=5*10^2*10

    5,000. 5,000 what though?

    Even with a proper π value, it still doesn’t make sense… 3,141.59265359

    • EddoWagt@feddit.nl
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      5 months ago

      What? Its just the volume, without units. What part of it doesn’t make sense?

      • jordanlund@lemmy.world
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        5 months ago

        Well, a r=10 and h=10 doesn’t mean much without units. 10 what? Feet? Meters? Inches? CM?

        Let’s take the OG numbers and assume feet, so 5,000 cubic feet. That’s not a useful volume measurement.

        1 cubic foot of water = 7.48052 gallons

        So 5,000 cubic feet of water = 37,402.6 gallons. That’s a viable volume measurement.

        1 cubic meter = 1,000 liters.

        5,000 cubic meters = 5,000,000 liters.

        • FuglyDuck@lemmy.world
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          5 months ago

          The unit is unit.

          The math doesn’t care, and what you’re on about only really matters if the units don’t start as all the same or if you start converting between things.

        • EddoWagt@feddit.nl
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          5 months ago

          Well, a r=10 and h=10 doesn’t mean much without units. 10 what? Feet? Meters? Inches? CM?

          Its not supposed to mean anything, it’s about the equation not about the end result. We’re not calculating an actual cilinder

  • gimpchrist @lemmy.world
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    5 months ago

    As a dyscalculic, I can’t solve this but I don’t see a problem here… I see all you people freaking out that the little symbol thing equals five but it’s a little symbol thing haha it doesn’t have to be pie haha it could be a little symbol thing.