What field do you work in, and how many digits of pi do you use?
What field do you work in, and how many digits of pi do you use?
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?
I haven't typed the digits of pi for probably 20 years because it's defined as a double precision float in all the programming libraries I use.
Ya know, this thread has inspired me. I'm a sound engineer, and find myself yelling "check one two three four" in the michrophone to test it all the time. I'm gonna start reciting the digits of Pi instead, and then as I learn them, I'll progressively advance how many numbers of Pi that I use in my everyday job :D
I work at a library, though. I should probably just go with poetry or Douglas Adams or something, but this makes me sound much more impressive
baker. I measure pie based on how much I can fit in my mouth
Retail, and to my knowledge among all my coworkers we have used zero digits of pi.
When I code in C++ I use 15 digits of pi after the decimal point (double float) but I have only rarely coded for money and have never used pi for those work products, so again, zero digits on the clock.
Ditto for restaurant work, although 2 decimal points would be more than enough if I needed the volume of a cake or other round food.
I'm an auditor. Zero digits is the norm if I have to use Pi there is something VERY wrong
I'm a consultant and I use whatever Android calculator gives me
As a pilot I can't think of a time I've ever done numbers math with pi. Private pilots are taught to use an E6B flight computer, which is basically a device for accurately drawing and measuring the triangle you're looking to solve instead of doing algebra and arithmetic.
In the wood shop, if I do have to do algebra rather than just drawing a circle with a compass, I'll use 3.14, and I still have to round to the nearest 32nd of an inch.
Engineering student. I typically use whatever number of digits the calculator gives me in calculator computations, but that's unnecessary. IMO for a design, an engineer should use at least as many digits of pi as needed to not lose any significance due to truncating pi specifically. Practically, this means: keep as many significant digits as your best measurement. In my experience, measurements have usually been good for 3 significant digits.
For back-of-the-envelope or order-of-magnitude calculations where I only need to get in the ballpark of correctness, I'll use 3 (i.e., one significant digit). For example, if I order a pizza with a diameter of 12 inches, A ≈ 36 * 3 in^2 = 108 in^2 is a fine ballpark approximation that I can do in my head to the real area A = 36π in^2 ≈ 113.097... in^2 that my calculator gives me.
I work in trails, like what you might walk on, and in the rare case I need pi, I use 3.14. This week, we have a meeting to talk about some things on 14 March. I will be using cornbread because I do not know how to make a pie but I will eat the pie others make. I look forward to this meeting.
If anyone here wants a fun way to memorize more digits, enjoy this song!
Really glad I have a legit reason to share this old thing
Answering my own question: I work in web development and my usual value for pi is the standard JavaScript Math.PI. JavaScript uses 64-bit floats, which are accurate to about 15 decimal places. But that's how many digits the computer uses. For practical math, I don't think I've ever needed more than 2 digits of accuracy in an equation involving pi.
The State of Indiana tried to define it to 1 digit by law.
https://en.wikipedia.org/wiki/Indiana_pi_bill?wprov=sfla1
Thankfully, the bill was never passed.
Back in middle school I memorized this much of pi (for no good reason):
3.14159265358979323846264338327950288419716939937510
That’s far more accurate than I’ll ever need.
I rarely use pi. But when I do I only use 3 digits. I wish I could use less, but we still need to use change when we make purchases.
The digital field, and we use the first ten digits, especially when those first ten digits is some person's password with the password hint "easy as pi".
Chip R&D. We only use 1's, 0's if management is feeling generous. There are no circles, no need for pi.
In Biostatistics - only ever use pi in the variance of the logistic density. Using 3.14 gives substantially equivalent results to using arbitrarily large precision. But I use whatever my calculator or R give me.
Equipment engineering. Usually 2 if I'm doing math by hand. 5 for more accurate calculations.
Mechanical engineer here - Matlab uses 16 digits for pi(), so that's my go-to. When doing some larger thermodynamic simulations, I sacrifice some digits of pi to get more computational headroom. But that's only after I get really annoyed at the code, and it almost never helps (but rarely hurts, as well)
I can't say "professionally" but I learned CAD design with FreeCAD, and know the topological naming issue thoroughly.
Almost all "mystery" problems in CAD are due to a combination of the hacks that get around the Topological Naming Issue and π.
In CAD, you cookie, you brownie, you might even salad, but you stay the hell away from importing π as a reference on anything complex. For 3D printing, I never need better than 0.05mm so 3.1416.
Molecular biology. 4 digits.
I work in the Bakery field and our specialty is Pie.
Embedded engineer, working in education. I use 3 for mental estimations and whatever is stored in the calculator, I have happened to grab, for "precision" work. Sometimes I'll even round pi to 4, to build in some tolerance when calculating materials.
Usually 8 decimal places.
But I work in HASS so we don't have much call for pi.
I'm a nothing in particular, and I used to remember 100 digits. I could probably remember again in an hour.
Well, I have two answers. If it is mental math I use 3.1 and round up. If I am calculating something I care about I use my TI-86 which has pi to 14 digits.
Practically speaking, I don't often need to convert diameter to circumference but I do occasionally need to calculate area or volume and in those cases I have way more error in other measurements or assumptions (2 or 3 digits) so 5 digits of pi is more than enough.
Why would anyone use this fakenass number it makes no sense
I use 100,000,000,000,000
I use 100 trillion digits
I use 100 trillion digits
