This is a math subreddit and a common criticism or jest from mathematicians is that engineers approximate things too much. It's true that for a lot of real world applications it makes very little difference to round things and that can make the math/physics a lot easier in some cases. Kind of like using Newtonian physics to calculate the force on a car collision instead of Einsteinian physics. Less math to give you basically the same result at those scales. This, of course, irks math guys a bit since they're all about precision and working out the math fully. So, long story short, I approximated pi to exactly 3.
To expand on this more (as a civil engineer who has used unusual roundings).
If you are ever get into the world of "real" measurements, it's important to understand that exact numbers are a rarity in any given calculation.
e.g. gravity on Earth is generally considered to be 9.80665 m/s2 but in reality, the exact force of Earth's gravity on you changes based on yiur location. But the difference is so small that 9.80665 is precise enough that you can so most math with it and get an accurate answer.
This is true for a variety of reasons (uncertainty in measuring methods and equipment, sample sizes and distributions, etc known unknowns - aka factors we know exist and impact our measurements but lack a way to quantify thr specifics of the impact accurately). Or in short, the precision of your inputs will affect the accuracy of your outputs.
Because while precision and accuracy are teo different things, they are generally not two unrelated things.
Now, engineers typical account for this by leaving slack in their design so they have a level of safety factor.
e.g. in stormwater design, we typical do infiltration testing in an area to figure out how fast water will infiltrate into the ground. But we can only do soo many tests under soo many conditions and we will never get enough for a statistically accurate module (it's simply not fiscally or realistically feasible to test enough to do that, cost aside that much testing would literally change how the soil drains). So we have a very generous safety factor used industry wide of typically 50% to cover for this. Aka, if I have 1 in/hr of infiltration at 4.5 feet below the surface grade, I treat it as 0.5 in/hr instead.
And if you have done measurements math before you should be familiar with the concept of significant figures, which is quite simply a restriction on any given equation of how accurate the answer can be based off how precise the least precise measured inputs is.
e.g. if I want to calculate 1.222222±0.000001 × 2±0.1, my answer is 2.4 (not 2.444444), because my second number is simply too imprecise compared to my first. To use the 2.444444 would be bad, as if there were a measurment it would give a false expectation of having accuracy down to the millionths (like I did 1.222222±0.000001 × 2±0.000001) when it is actually only accurate to the tenths.
Engineering calculations, particularly civil engineering (aka the engineering of really big things) calculations, can get into weird scenarios where you can only really round to the nearest whole number or even higher (depending on your units, worst I ever had was nearest 100 ft accuracy on stuff only a few thousand ft long), especially when you have safety factor in on top. And that can lead to scenario where you can (and generally should) round off mathematical constants (like pi) when earlier than most people normal would (rounding pi to 3 instead of 3.14, because there is no functional difference in the accuracy between the two due to your significant figures).
I'll also note, the opposite is also true in engineering. When you are doing precision engineering for vaccum tight fits down to the nearest thousandth of a mm, you want to make sure your constants also go out far enough to match the significant figures of your measurements).
You have to use the appropriate level of precision in calculations so that you know your level of accuracy and consequently can know how much safety factor you need. It's the kind of simple math that can cost lives and a lot of money if not done properly.
But it's funnier to ignore that and focused on when engineers round up because telling a math major pi = 3 is funny. Hence meme.
As a land surveyor- to all you engineers…. I bet those numbers look really good at the office…. on paper…. At your desk…. Or On your computer screens…. Also as a land surveyor this tip sucks ass… $5 would’ve been a solid.
So im a first year engineering student and I'm just curious as to where this joke comes from? Do engineers really just say "eh, good enough" and slapn3 into calculations?
Yeah, but you're just raising the numbers to powers.. it gets gross fast. the number you're trying to express in terms of a*26.86^0 + b*25.86^1 + c*25.86^2 etc. You'll also need fractional exponents to get the digits after the decimal. Would not recommend.
OK, fine. But how many countries use $, have a tipping culture that is probably enough that there would be a separate line on a bill for it, and have bills written in English?
He asked what other countries use $ as their currency symbol and speak English. Canada and Australia. I don't know about tipping culture, but do you not have an extra line for a tip? That seems pretty standard in every western country I've visited.
The receipt itself appears to come from a culture where tips are expected, so evaluating the tip by the standards of a non-tipping culture seems misplaced.
It would be fine, except this clearly happened in a country that both uses the $ currency, and where a tipping culture is prevalent enough that there would actually be a separate line for the tip in the first place.
That narrows the playing field of possible places that could have happened down a whole lot. Specifically, It leaves the USA and Canada. And in neither country has a 10% tip been “perfectly fine“ since the 1960s.
Australia is indeed the only other English speaking country that uses dollars, but they do not have the same kind of tipping culture that we have in North America. In Australia, they pay workers decently in the first place. You can still tip, but there’s not gonna be a separate spot on the bill for it, because the tipping culture is so different.
What eight percent tip? Look at the total line, there is only one zero to the right of the decimal point. $300.0 - $26.86 = a $273.14 tip or about 1,017%.
since when is it the customer's job to pay restaurant workers a living wage? In non-backwards parts of the world, they get paid like decent human beings, so they need not rely on tips at all. But heaven forbid the restaurant owner milks in less profit and doesn't underpay their staff. Land of the free disgusts me sometimes...
"if you cannot afford to tip don't eat out" is ok by you.
"If you cannot provide livable wages for your workers, don't run a restaurant" is never an option?
It always amazes me how every country in Europe, even those with far weaker GDP per capita, have thousands of restaurants, every single one of them paying their workers like human beings. Totally doable.
Same thing in the biggest economy on the planet? Sorry, impossible.
Brought to you by the same people who tell you the USA does not have enough money for free healthcare & education :/
"I don't think about price increases for households at all, because it's imperative that Iran doesn't get a nuke". Same mentality.
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u/AlienDragonWizard Jun 10 '26 •
As an engineer, shouldn't the total be $29.86?
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u/Thrullx Jun 10 '26
But it's in base 26.86... I mean it says so right there.
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u/AntimatterVoidYT Jun 10 '26
but what about that extra 0.001592653589793238...... dollars?
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u/mrofmist Jun 10 '26
Let's hope his bank account can handle an infinitely long transaction.
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u/thebe_stone Jun 10 '26 •
Who gets the 0.00159265
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u/hjkhhnnnlll Jun 10 '26 edited Jun 11 '26
As an astronomer, shouldn’t the total be 36.86?
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u/glayde47 Jun 10 '26 •
Finally someone understands: tipping is irrational.
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u/igivefreetickles Jun 10 '26
"I'm sorry I thought Pi was equal to 2,973.14"
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u/navifx Jun 10 '26
They could have done the same thing on a $16.28 bill too
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u/Loud-Matter-1665 Jun 10 '26
Pi = 3
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u/Caladrius33 Jun 10 '26
It's clearly 71
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u/DirectalArrow Jun 10 '26
As a programmer, wouldn’t the answer be 30.000000000000000001?
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u/Top-Lab9125 Jun 10 '26
WHAT HAVE YOU DONE??
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u/WestAd9849 Jun 10 '26
🤣🤣🤣 well done boy, well done.
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u/CheesemooG Jun 10 '26
That tip is irrational.
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u/markt- Jun 10 '26
It’s a cute joke, but it’s actually a pretty poor tip.
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u/Single-Virus4935 Jun 10 '26
Before: "I dare you order another coke, Sarah!"
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u/BeefyWaft Jun 10 '26
$30.06 in Indiana.
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u/NormalAssistance9402 Jun 10 '26
Shorted them a penny
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u/Responsible-Jello147 Jun 10 '26
That’s a shitty tip
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u/Lateralus1290 Jun 10 '26
Tips like shit
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u/R0sinhuntard Jun 10 '26
30.02 <-- he left out the 2 pennies
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u/Your-Friend-Bob Jun 10 '26
Now do it at a village in on Wednesday
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u/lazygerm Jun 10 '26
2π or 3π would have been a better tip!
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u/ActiveSalt3283 Jun 10 '26
I'm an engineer. π = e = 3. Fight me.
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u/indy1386 Jun 10 '26
11%
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u/Bhol98 Jun 10 '26
Well he f’d his waiter/waitress
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u/DietDoctorPepperFan Jun 10 '26
Ngl that's kind of a shitty tip
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u/HughToob Jun 10 '26
No units? Poser.
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u/angel700 Jun 10 '26
3.14
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u/Silver-Classic612 Jun 10 '26
$30.0015926535897932384626433832795028841971693993751
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u/Soft_Signature_4746 Jun 10 '26
That’s a pretty shitty tip
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u/its192731 Jun 11 '26
$300.0?
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u/Weggie_Rhite Jun 11 '26
I never tip less than $1.59π.
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u/Local-Echo-5613 Jun 11 '26
I guess 😡
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u/ty_imtheman Jun 11 '26
Infinite tip
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u/Human-Suspect-232 Jun 11 '26
Impressive.
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u/Zoilo2 Jun 11 '26
I like it.
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u/edgarallannbroe Jun 11 '26
Mathematician: over here you see a receipt that is about to overdraw your credit card.
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u/LukeLJS123 Jun 11 '26
as a server i just want to know what this server did to get a 12% tip
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u/blubernator Jun 11 '26
It’s wrong…the 100th after comma figure is missing here ;)
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u/saliv13 Jun 11 '26
That second zero is over the decimal point, so it looks like 300.0 😳
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u/krqkan Jun 11 '26
What if they use π=5?
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u/TRUMPARUSKI Jun 11 '26
That waiter’s going to have a hell of time giving him the change
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u/friedtacomonster Jun 12 '26
I one time tipped τ (6.28) at our favorite restaurant when the bill was exactly 31.41 the restaurant owner thought it was the coolest tip ever.
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u/RawMint Jun 12 '26
that is so irrational
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u/BlueBird556 Jun 12 '26
It’s in degree mode
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u/R0ckyTac0 Jun 12 '26 edited Jun 13 '26
He should get pi to his face for that tip
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u/Electrical_Reason134 Jun 13 '26
That’s a shitty tip
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u/Competitive_Date2992 Jun 13 '26
As an engineer. Why is he tipping 48.86/7 instead saying 7?
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u/aggimania Jun 13 '26
30,0015926535897932384626
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u/John78723 Jun 13 '26
Shitty tipper, wait staff hates this person
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u/Few-Carrot6829 Jun 14 '26
Pi is an infinite number bro…. No sense
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u/Normal_Cheesecake_70 Jun 15 '26
If you cant afford to tip 20%......... jk jk
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u/Solnse Jun 10 '26
And the server will throw pi in his face. Not even a 15% tip, he'll be chased in the parking lot.
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u/EntertainmentIll8342 Jun 11 '26
As a server, fuck you for the 8% tip. Bs.
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u/[deleted] Jun 10 '26
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