Mathematics
 
Question:
Avatar

What is Pi? Who discovered it? How did they find out that number has almost infinite digits?

By Ragnarok Asked May 31 2004 8:05PM
1
Pts
 
 
Rate Question
Answer Question Help someone!
Get the latest questions in Mathematics
flag

Welcome to Answerbag, a community of people sharing what they know.
Sign up now to ask a question or help someone else by giving an answer!

signup now
Sort answers by: Rating | DateArrow Down
 

Top Answer out of 14

by singwell-is off researching a lot on Feb 16, 2007 at 12:20 am Permalink

Avatar
Wikipedia: The mathematical constant π is an irrational real number, approximately equal to 3.14159, which is the ratio of a circle's circumference to its diameter in Euclidean geometry.
Pi is special because , no matter how many decimal places you take it to, it never repeats a number or a sequence of numbers.
The numerical value of π truncated to 500 decimal places is:

3.1415926535897932384626433832 795028841971693993751058209749 44592307816406286
208998628034825342117067982148 086513282306647093844609550582 231725359408128481 117450284102701938521105559644 622948954930381964428810975665 933446128475648233 786783165271201909145648566923 460348610454326648213393607260 249141273724587006 606315588174881520920962829254 091715364367892590360011330530 548820466521384146 951941511609433057270365759591 953092186117381932611793105118 548074462379962749 567351885752724891227938183011 94912
The value of π has been known in some form since antiquity. As early as the 19th century BC, Babylonian mathematicians were using π = 25⁄8, which is within 0.5% of the true value.

The Egyptian scribe Ahmes wrote the oldest known text to give an approximate value for π, citing a Middle Kingdom papyrus, corresponding to a value of 256 divided by 81 or 3.160.

It is sometimes claimed that the Bible states that π = 3, based on a passage in 1 Kings 7:23 giving measurements for a round basin as having a 10 cubit diameter and a 30 cubit circumference. Rabbi Nehemiah explained this by the diameter being measured from outside rim to outside rim while the circumference was the inner brim; but it may suffice that the measurements are given in round numbers.


Principle of Archimedes' method to approximate πArchimedes of Syracuse discovered, by considering the perimeters of 96-sided polygons inscribing a circle and inscribed by it, that π is between 223⁄71 and 22⁄7. The average of these two values is roughly 3.1419.

The Chinese mathematician Liu Hui computed π to 3.141014 in AD 263 and suggested that 3.14 was a good approximation
10
Pts
 
 
Rate Answer
 
flag
Comments show all comments Show More
Avatar Alan Feb, 17 2007 at 03:18 PM
The bible even mentions it? cool.
Avatar singwell-is off researching a lot Feb, 17 2007 at 10:29 PM
apparently, it can be inferred from the information given in the passage, 1 Kings 7:23 7:23 "And he made a molten sea, ten cubits from the one brim to the other: it was round all about, and his height was five cubits: and a line of thirty cubits did compass it round about." This shows that they understood that pi was 3, not the most accurate by today's standards, but not too bad, considering this was 10 centuries BC.
I just found this site: looks interesting.
http://www.apocalipsis.org/difficulties/pi.htm
Avatar The Music Roob Ninja Nov, 30 2008 at 06:51 AM
Brilliant answer, the only thing I would add is that Pi is the equivalent of 180 degrees in radians. Radians are a unit of angle such that the length of the arc of a 1 radian segment is equal to it's radius. So if you had a cake (I avoided saying pie) and cut a piece so that the lengths of all its sides (including the curved out, measured along the curve) were equal, the angle in the middle would be equal to one radian. Pi radians is equal to 180 degrees, which is why it is the ratio of circumference to diameter.

Answer 2 out of 14

by slothmister on Jan 2, 2008 at 5:01 am Permalink

Avatar
Pi is the relationship between the area of a circle and the square of the radius of that circle.
Aprox value is 3.14
Answer originally posted in response to What is pi
6
Pts
 
 
Rate Answer
 
flag
Comments (be the first to comment)

Answer 3 out of 14

by anguilla on Jun 1, 2004 at 10:08 pm Permalink

Avatar
This answer was last edited on: Mar 15, 2005
Pi is the ratio of the circumference of a circle to its diameter. To put it another way, it's the length of the circumference divided by the length of the diameter.

Pi always works out to be the same value, no matter what size the circle is. So Pi is a Big Deal because it lets you easily measure the length of the curved line that makes up a circle.

Pi = C/D, so if you know the diameter and Pi, you can calculate the circumference.

IF you do the math, and divide the circumference by the diameter, you'll get 3.1415926535897932384626433832 7950288419716939937510.....
-- where the dots represent the fact that no matter how long you keep dividing, it never comes out even and the pattern of numbers doesn't repeat. It has reportedly been calculated out to 206 billion digits!!

There are charts that describe the history of Pi, which goes back to the Babylonians (2000 BC), and how accurately (or inaccurately) Pi has been calculated through the years. I'm sorry I can't make it appear in neat columns here, but you can see it neatly if you go to http://www-gap.dcs.st-and.ac.uk/.../Pi_chronology.html

Even though the rough value of Pi was known long before his time, the first theoretical calculation seems to have been carried out by Archimedes of Syracuse (287-212 BC).
--- http://www-gap.dcs.st-and.ac.uk/.../...ugh_the_ages.html

I have altered the answer in response to comments from readers. Sorry for any mistakes.
6
Pts
 
 
Rate Answer
 
flag
Comments show all comments Show More
Avatar Quirkie Sep, 16 2005 at 10:47 AM
Avatar Akshay Agarwal Mar, 07 2005 at 08:56 AM
this is what I was searching for.
Avatar Les Toth Mar, 15 2005 at 07:45 PM
Very unhelpful reference to 22/7

Answer 4 out of 14

by Jack wears love COAT on Jan 2, 2008 at 5:04 am Permalink

Avatar
Consider any circle of any radius.
The circumference of this circle always is little more than 3 times its diameter.
And this "little more" is always one-seventh of its diameter.
So the circumference is always 3+(1/7) of its diameter, which you can write as (21/7)+(1/7)=(22/7).
This value, 22/7 is called as "pi".
Answer originally posted in response to What is pi
4
Pts
 
 
Rate Answer
 
flag
Comments
Avatar tsunami0603 Feb, 26 2009 at 05:50 PM
Pi does not equal 22/7. If it did, it would be a rational number. 22/7 = 3.14285714
pi = 3.14159265
22/7 and pi only round to the same number (3.14)

Answer 5 out of 14

by Lee the Greek on Jan 2, 2008 at 5:02 am Permalink

Avatar
Pi or π is one of the most important mathematical constants, approximately equal to 3.14159. It represents the ratio of any circle's circumference to its diameter in Euclidean geometry, which is the same as the ratio of a circle's area to the square of its radius. Many other formulas from mathematics, science, and engineering include π. It is an irrational number, which means that its decimal expansion never ends or repeats.

For more information on Pi visit http://en.wikipedia.org/wiki/Pi
Answer originally posted in response to What is pi
2
Pts
 
 
Rate Answer
 
flag
Comments (be the first to comment)

Answer 6 out of 14

by Isaac on Apr 16, 2009 at 8:20 am Permalink

Avatar
It doesn't have almost infinite digits. It was discovered that it has about 12 trillion decimal places, which is no where near infinity. :-)
0
Pts
 
 
Rate Answer
 
flag
Comments (be the first to comment)

Answer 7 out of 14

by Alicebee123 on Mar 12, 2009 at 2:27 pm Permalink

Avatar
opps I learned that in 7th grade im sorry!
0
Pts
 
 
Rate Answer
 
flag
Comments (be the first to comment)

Answer 8 out of 14

by Alicebee123 on Mar 12, 2009 at 2:25 pm Permalink

Avatar
Pi is 3.14159265358979323846 etc. thats on top of my head! Pi is 200bc years old and you know what im only 7th grade and i know that!Pi keeps going on forever it never stops! PI day is officially march 14th! PI IS THE NUMBER OF TIMES A CIRCLE'S DIAMETER WILL FIT AROUND ITS CIRCUMFERENCE!PI IS THE 16TH LETTER OF THE
GREEK ALPHABET.In 1706 William Jones first gave the Greek letter "π" its current mathematical definition.All the digits of Pi can never be fully known.Three point one four one five nine two
It’s been around forever - its not new
It appears everywhere in here and in there
Its irrational I know but its true!The 3,000,000,000th decimal digit of PI is an 8. There thats all I know about Pi ask more questions and ill answer them!
0
Pts
 
 
Rate Answer
 
flag
Comments (be the first to comment)

Answer 9 out of 14

by Roger Kovaciny on Dec 29, 2008 at 1:13 pm Permalink

Avatar
It slays the natives if you can tell them that pi equals 3.1415926--which is easy to remember from the number of letters in the phrase "Yes, I want a drink; alcoholic of course."
0
Pts
 
 
Rate Answer
 
flag
Comments (be the first to comment)

Answer 10 out of 14

by Ivo on Dec 29, 2008 at 12:31 pm Permalink

Avatar
But what is the Platonic marriage number, where the product of pi digits 3141592654 = 129,600?
0
Pts
 
 
Rate Answer
 
flag
Comments (be the first to comment)


Add an Answer

What is Pi? Who discovered it? How did they find out that number has almost infinite digits?

How to write a good answer
Your answer:

Display answer in fixed-width font (good for tables or text diagrams)

Answers must adhere to our Terms of Use

To create links, just type the address with no HTML code. Use the Preview button at the bottom to verify.

You can edit your answer at any time.

Add Video Add Iimage


Important: Answerbag cannot guarantee the accuracy of answers submitted by members, and we recommend that you use common sense when following any advice found here. Read full disclaimer.