Why is π accepted?
Basically, people in 18XX found out that a circle's diameter to circumference has a ratio of 22:7.
They invented π and said that it's the correct way to measure a circle, and everybody followed that rule till this day.

They were never accurate.
π is an irrational number. It is never ending and it's not real. Meaning the calculations you get are 'quite close' but it is NEVER the right answer.

Example : I make a simple 20cm2 area square cake. If I melt that cake and change it into a circle shape, using π I will get 19.998476286...which is a wrong measurement. Every digit behind it is wrong. It gives an infinite amount of wrong digits. 19.9 < 20

Why are people accepting π without knowing it's wrong? People have blindly follow the wrongs in 18XX? :ujel:
Zuletzt bearbeitet von Irene ❤; 26. Okt. 2022 um 10:14
Ursprünglich geschrieben von Fumo Bnnuy n Frends:
Ursprünglich geschrieben von Irene ❤:
Basically, people in 18XX found out that a circle's diameter to circumference has a ratio of 22:7.
They invented π and said that it's the correct way to measure a circle, and everybody followed that rule till this day.

They were never accurate.
π is an irrational number. It is never ending and it's not real. Meaning the calculations you get are 'quite close' but it is NEVER the right answer.

Example : I make a simple 20cm2 area square cake. If I melt that cake and change it into a circle shape, using π I will get 19.998476286...which is a wrong measurement. Every digit behind it is wrong. It gives an infinite amount of wrong digits. 19.9 < 20

Why are people accepting π without knowing it's wrong? People have blindly follow the wrongs in 18XX? :ujel:
lemme tell you a story

some guy or girl i think guy reworked a keyboard to be all vowels on the left side and then the right is all constanents.

So he trained and showed how you can surpass qwerty keyboards word per minute by using the keyboard.

They could change it but:
-people were already trained with qwerty keyboards
-lots of training seminars and software to teach how to use the keyboard
-to replace all qwerty keyboards everywhere would take alot more $$$$ for a few extra words per minute.


Like the 5 gorillas experiment


THAT'S JUST THE WAY THINGS HAVE ALWAYS BEEN DONE!!!
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Samurai 25. Okt. 2022 um 20:45 
Its accepted because everyone loves pie.
Ursprünglich geschrieben von kbiz:
Ursprünglich geschrieben von Pieshaman:
if I would expand 1 atom to the size of the universe. then a planck length would be the size of a small house or tree, compared to that universe

The amazing thing about the Planck constant is everything vibrates at whole number multiples of that base frequency.

Scale has always fascinated me. From a neutrino to the size of the Universe.

If you get down the quantum level, everything is based on probability. Quantum jumps, quantum tunneling, superposition, particle-wave duality, quantum entanglement... all very strange.

eh yes but I think you are mixing up planck contant and planck length here.
planck constant is about energy not length:steamhappy:
kbiz 25. Okt. 2022 um 21:35 
Ursprünglich geschrieben von Pieshaman:
Ursprünglich geschrieben von kbiz:

The amazing thing about the Planck constant is everything vibrates at whole number multiples of that base frequency.

Scale has always fascinated me. From a neutrino to the size of the Universe.

If you get down the quantum level, everything is based on probability. Quantum jumps, quantum tunneling, superposition, particle-wave duality, quantum entanglement... all very strange.

eh yes but I think you are mixing up planck contant and planck length here.
planck constant is about energy not length:steamhappy:

I did say scale fascinates me. Gotta allow me to talk about the Planck constant instead. We're just taking about interesting sh!t.

Did you know quarks comprise only 1% of the mass of protons and neutrons and that 99% of the mass comes from the interaction between the quarks themselves?

Hey, did you why you were banned? Trying to figure out your transgression.
The cake is the lie. Please spare the pie.
Ursprünglich geschrieben von Irene ❤:
Why are people accepting π without knowing it's wrong? People have blindly follow the wrongs in 18XX?:ujel:


Well, no.. anyone who uses pi quite often, is well aware of the rounding errors and dangers of not using enough figures for accuracy calculations. People are not blind, or else you would have very many more critical failures in dangerous machinery lol.

to answer the rest of the 'why is it accepted' question:

-all circles are the same. the only difference being the size. radius, diameter, circumference or area.

-since they're the same apart from size, the three measurements are all related in the same way for every circle.

- the radius is half the diameter, the circumference is pi times the diameter, the area is pi times the radius squared.

so pi is a common ground that you can use to express any circle, or chunk of a circle that can fit into a different geometric shape.

yes, it is unfortunate and a nuisance that pi is irrational, and is approximated.

but, until you find a better way to relate them, in pi we trust.

so, i'll be waiting for your elegant system of mathematics to provide exacting answers to many inaccuracies we currently have, which may catapult our civilization into the future. exciting.
Ursprünglich geschrieben von MinionJoe:
NASA engineer confirmed that we only need to go out to 5 decimals
Imagine they found a planet which is 456789km in diameter. What is the surface length of it?

5 digits = 3.14285 x 456789 = 1435,495 km
6 digits = 3.142856 x 456789 = 1435,622 km

If NASA used 5 digits, they shrink the planet by 127km.

The measurement rule is wrong. - Be it to increase or decrease the digits, NASA will only be further away from the truth...
Ursprünglich geschrieben von Hammer Of Evil:
- all circles are the same.
- they're the same apart from size
- a common ground that you can use to express
Err ya.. it means they are measuring things using a ratio approach, but that is clearly incorrect. If I can always do 3.5x more push ups than you, you did 10 I'll do 35. But when I do 20, it means you will have to do 5.71428+infinite digits of push ups. How is that even possible. :erune: Math's best definition is "the science and study of quality, structure, space, and change" and that result is "ahh not possible" all because of π.

The push up count is fixed. The circumference length is fixed. There is no infinite digit. People just don't know the right way to measure it.

Ursprünglich geschrieben von Hammer Of Evil:
until you find a better way to relate them, in pi we trust.
Err.. so your answer to topic "Why is π accepted" is "We accept the wrong as a rule because we can't find the right answer"? : x
Zuletzt bearbeitet von Irene ❤; 25. Okt. 2022 um 23:57
Ursprünglich geschrieben von 🌸 Wraith 🌸:
removing it would result in the previous digit in "3.142856" to raise by one, and make it "3.14286. I think we had this lesson in elementary school.
The difference is less than 2 km.
Err yes it's call rounding up / down. The 127km did not disappear. It's being overwritten by another wrong number. If your salary is $3144 and accounts gave you $3100 instead, would you not question where is that $44? : P

Imagine this, the planet is colonized. You bought a house there. A week later they call you up and say opps your house disappeared because we round up the surface length and now we can't find it. It's less than 2 km (2000m) but it still hits your 50m house. You might go "what nonsense, where did you guys hide my house?

and that is π. All the wrong guessing. Infinite digits of guessing.
Zuletzt bearbeitet von Irene ❤; 26. Okt. 2022 um 0:00
oh i see. ignore everything that goes against your 'proof.'

well, mathematics doesn't work like that, but you keep on doing what you want. lol.
How many points make up the circumference of a circle?

It's stuff like that that makes us have to use pi in calculations, otherwise after enough math, you're left with a really bad answer that makes less sense
22/7 is not a "rule", unless you mean a rule of thumb[en.wiktionary.org]. It's an approximation of pi.


Pi is irrational, though it is also real. Real in the sense of being in the category known as "real numbers", which includes literally any number you can fit in a single dimension -- i.e. if you draw a straight line that's infinitely long, you can find any such number as a distance between two points on it.

Irrational just means you can't express it as a ratio. There are an infinite number of numbers that can't be expressed as ratios. For example, this includes all the square roots of positive numbers that aren't perfect squares. You can draw a right triangle with legs that are one inch long each, and you can measure the length of the hypotenuse, even though it's the square root of 2, which is irrational. So it's still a real number.

As for exactly what number pi is:
* yes, it does have an exact value.
* it just can't be written down exactly using our base ten number system.

In a way, it's like how we can't write one-third exactly without using a fraction symbol or something to indicate a repeating decimal. Except in the case of pi, it just happens that it doesn't repeat.

Not all decimals (i.e. numbers with nonzero digits past the decimal) repeat. For example, consider the number implied by the following pattern:

0.1101001000100001000001000000...

This won't ever repeat. In fact, because it's a non-repeating decimal, it's irrational, like pi. But it's still a number.


That said, how do we use an irrational number? Why do we have 22/7?


That's because the numbers we actually need in real life are often approximations anyway. If you need to cut 2 inches off a piece of wood, you're not measuring down to the atom and making a straight line of atoms where the cut is. You're probably just gonna use a pencil and then saw it off. It's not exactly 2 inches you've cut off, it's a good enough estimate of 2 inches, as you can measure from a ruler on hand and mark with a pencil. And it's probably good enough for pretty much anything you'd use that wood for; you don't actually need to know if it's exactly 2.0000000000000000000000 inches.

22/7 isn't pi. 355/113 isn't pi. 3.14 isn't pi. 3 isn't pi. But depending on what you're using pi for, it might be good enough. If I need to know what length to cut a sheet of plastic to make a ring around a circular cake, I can probably get away with 3.14 for pi. If I'm planning to deposit a very thing layer of chemical coating onto a smoothly polished metal cylinder, I might need more digits. Different situations require different levels of precision.

Heck, a lot of the time when I headmath I just use 3 and run on "pi is a little more than this". So 2 pi is a little more than 6, 3 pi is a little more than 9, and so on.

In math, if you need the exact value of pi, chances are you're working in some context where writing down lots of digits doesn't even matter. So you can just use the pi symbol (technically the lowercase Greek letter pi) for it and literally just leave it there. If you need to get a numeric value, you can then decide -- based on what you're using it for -- how much precision you need, or in other words, how many digits or how complicated of a fraction you want to use.

For example, what's the period of the basic sine function? 2 pi. You don't even need to approximate it unless you're, say, building or measuring something that makes use of it. Plus, it's way faster to write symbols like that than to try to get their decimal approximations. It's just better all around if you don't need the approximations.
Zuletzt bearbeitet von Quint the Alligator Snapper; 26. Okt. 2022 um 2:18
Its an interesting discussion because ya, youre right.

I havent watched this in years, but Ill drop it for anyone interested. This guy has a very different approach to mathematics and I remember he calculates that ratio slightly differently. He also has a lot of perhaps weird theories about numbers.

I am not offering this as a proponent of anything he says; its just a bit....different.

https://youtu.be/Xw9lTB0hTNU
Zuletzt bearbeitet von AmsterdamHeavy; 26. Okt. 2022 um 2:44
Siluva 26. Okt. 2022 um 2:45 
I got maths class tomorow, I can ask if you want.
Irene really opened up a math textbook and said "you know what, these professors didn't account for ME" then wrote over the entire thing with marker
Angel 26. Okt. 2022 um 3:07 
Just come by to say Welcome Back Irene! <3 :hp_kyu:
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