What is pie? (Math)?

Answer 1

Pi (it's a Greek letter) is the ratio of any circle's circumference to its diameter. It's usually expressed as 3.14, but is in fact a nonrepeating, nonterminating decimal number.

3.14159265358979 should be more than sufficient for any use outside the most advanced math classes.

Answer 2

By definition, pi is the ratio of the circumference of a circle to its diameter. Pi is always the same number, no matter which circle you use to compute it.
For the sake of usefulness people often need to approximate pi. For many purposes you can use 3.14159, which is really pretty good, but if you want a better approximation you can use a computer to get it. Here's pi to many more digits: 3.14159265358979323846.

The area of a circle is pi times the square of the length of the radius, or "pi r squared":

A = pi*r^2
A very brief history of pi

Pi is a very old number. We know that the Egyptians and the Babylonians knew about the existence of the constant ratio pi, although they didn't know its value nearly as well as we do today. They had figured out that it was a little bigger than 3; the Babylonians had an approximation of 3 1/8 (3.125), and the Egyptians had a somewhat worse approximation of 4*(8/9)^2 (about 3.160484), which is slightly less accurate and much harder to work with. For more, see A History of Pi by Petr Beckman (Dorset Press).
The modern symbol for pi [] was first used in our modern sense in 1706 by William Jones, who wrote:

There are various other ways of finding the Lengths or Areas of particular Curve Lines, or Planes, which may very much facilitate the Practice; as for instance, in the Circle, the Diameter is to the Circumference as 1 to (16/5 - 4/239) - 1/3(16/5^3 - 4/239^3) + ... = 3.14159... = (see A History of Mathematical Notation by Florian Cajori).
Pi (rather than some other Greek letter like Alpha or Omega) was chosen as the letter to represent the number 3.141592... because the letter [] in Greek, pronounced like our letter 'p', stands for 'perimeter'.

Answer 3

Exact value of pi is not possible, because howsoever thin line a circumference of a circle may be, it will still have an outer margin and an inner margin. Outer margin will always be longer than the inner margin. So one can never measure exact length of a circumference. If you try to straighten a circumference into a straight line, molecules in the material of outer margin will get overcrowded and compacted and may protrude out as tiny bumps, and the molecules of the material in the inner margin will get stretched out - some inter-molecular bonds may get broken by the stretching force - minute pits may form. Secondly the cut ends of the straightened circumference wont be clean cut , because of differential length of the outer and inner margin lines (as they were in the circle). So if we can t measure precise length of the circumference ever, howsoever thin the circumferential line may be, how can we measure the precise value of pi?
I am not a mathematician, just a layman.

Answer 4

It's spelled "pi" not "pie" (that's the thing you eat).

Pi is the ratio of the circumference of a circle to its radius. This ratio is the same for every circle, no matter how big or how small. The formula is:

c = 2pi* r where c is the circumference, r is the radius, and pi = the magic, non-rational ratio 22/7.
In decimal form that works out to about 3.1417 -- but pi keeps going on irrationally forever -- it's been calculated to well past 1 million digits to the right of the decimal point. :)

Answer 5

The word is pi, written π, and it is a special number that lets you calculate the circumference (perimeter) of a circle, and its area. The number has an infinite number of decimal places, but the first few are 3.14159...

Answer 6

Pi is a number that represents the ratio of the area of a circle. It is a numer with an infinite number of digits.

3.14159....

It goes on forever!!

Answer 7

3.1459.....
It's a number that doesn't terminate.
It's celebrated March 14

Answer 8

Pie In Math

Answer 9

pi is the ratio of a circles circumfrance to its diameter. It a long number 3.14........ it goes on forever with out repeating.

Answer 10

A constant used to find the area and circumference of a circle.