Doing some pipeline welding math homeworks and...

"claramag, Mustaco Master" (claramag) 10/05/2014 at 20:30 • Filed to: offtopic

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"NPS 3 Sch 80 (NPS 3 Sch 80 means outside diameter=3.500") Find outside circumference"

me- ok so simple pi stuffs, 3.142 rounding to 3rd deci to match numbers given, gives a circum of 10.997"! Easy breezy lemon squee—

'Sorry, the correct answer was 10.9" '

GhostZ > claramag, Mustaco Master 10/05/2014 at 20:34

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I've seen online quizzes that have a +/- range for a correct answer, usually to whatever decimal place it's rounded to.

Josh Welton > claramag, Mustaco Master 10/05/2014 at 20:37

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As a weldor....burn your homework.

Rainbow > claramag, Mustaco Master 10/05/2014 at 20:40

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Technically, pi should be 3.142 since the next digit is a 5. But I doubt it would have made a difference there. :P

claramag, Mustaco Master > GhostZ 10/05/2014 at 20:47

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a +/- range for rounding error, alright that I can understand. But there's no hint on rounding and it's exact answer or bust. So I'm astounded how they got 10.9 from, at the very least, 10.99 (if rounding pi to 3.14)

claramag, Mustaco Master > Rainbow 10/05/2014 at 20:53

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Ack, thanks i missed that! TBH i generally use pi to the 9th deci but i forgot to round when i cut it off

claramag, Mustaco Master > Josh Welton 10/05/2014 at 20:54

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IT FRUSTRATES ME TO NO END

GhostZ > claramag, Mustaco Master 10/05/2014 at 20:55

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I mean, technically the correct answer would deal with significant digits depending on the other inputs. Which should actually be more digits than 10.99.

Josh Welton > claramag, Mustaco Master 10/05/2014 at 21:13

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Just wait until you're in class, possible slightly intoxicated, screaming at the professor about how this has nothing to do with real world work and the police are called and you're expelled but then it's reduced to a suspension and you're allowed to finish your apprenticeship. Hypothetically speaking.

claramag, Mustaco Master > GhostZ 10/05/2014 at 21:23

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Having taken no real math courses, significant digits is a foreign concept. Still, I think we can all agree that the course in question's math is bad and they should feel bad

Also can we all collectively agree that complex maths with ft/in is a horrible idea and the US should just bite the bullet and go metric already ffs?

claramag, Mustaco Master > Josh Welton 10/05/2014 at 21:28

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A peculiarly specific hypothetical is the best hypothetical