What's the exact "pi"?

Answer 1

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

Pi is an infinite decimal. Unlike numbers such as 3, 9.876, and 4.5, which have finitely many nonzero numbers to the right of the decimal place, pi has infinitely many numbers to the right of the decimal point.

If you write pi down in decimal form, the numbers to the right of the 0 never repeat in a pattern. Some infinite decimals do have patterns - for instance, the infinite decimal .3333333... has all 3's to the right of the decimal point, and in the number .123456789123456789123456789... the sequence 123456789 is repeated. However, although many mathematicians have tried to find it, no repeating pattern for pi has been discovered - in fact, in 1768 Johann Lambert proved that there cannot be any such repeating pattern.

As a number that cannot be written as a repeating decimal or a finite decimal (you can never get to the end of it) pi is irrational: it cannot be written as a fraction (the ratio of two integers).

Pi shows up in some unexpected places like probability, and the 'famous five' equation connecting the five most important numbers in mathematics, 0, 1, e, pi, and i: e^(i*pi) + 1 = 0

pi is not exact..

Answer 2

There is no exact pi here's a few digits for you

3.1415926535897932384626433 83279502884197169399375105 82097494459230781640628620 89986280348253421170679
82148086513282306647093844 60955058223172535940812848 111745028410270193852110 555964462294895493038196
44288109756659334461284 7564823378678316527120190 9145648566923460348610454 326648213393607260249141273
7245870066063155881748815 2092096282925409171536436 78925903600113305305488204 66521384146951941511609

Answer 3

Since pi has an infinitely number of digits after the decimal that have no pattern, it would be futile stating exactly what pi is. That's why it is expressed as pi.

Pi is the ratio of a circle's circumference to its diameter.

I can tell you what PI is not: it's not 22/7. Nor is it 3.14. Pi is pi.

Answer 4

as has been said before, pi is an irrational number that goes on and on and on. if i'm not wrong, people have dedicated their lives to finding the exact value of pi and the closest they've gotten to so far is... well, many, many pages of digits.

pi doesn't repeat itself, which someone said. also, i think there are some guiness world record(s) set about pi you might want to read up in their book.

Answer 5

Pi is an irrational number(it means that pi can't be expressed in the form p/q where p,q belongs to real number) and it is not algebraic. It is a transcendental number. You can never know the exact and complete value of phi. But it is not essential to know this complete value(which is impossible) for practical purpose.
Actually by knowing the value of phi to about nine decimal place you can even work out the radius of the universe and the radius of a hydrogen atom precisely.

Answer 6

Actually,the exact "pi"is 22/7.

Answer 7

3.1415926535897932384626433832795028841971693993751058209749445923078164062862089986280348253421170679821480865132823066470938446095505822317253594081284811174502841027019385211055596446229489549303819644288109756659334461284756482337867831652712019091456485669234603486104543266482133936072602491412737245870066063155881748815209209628292540917153643678925903600113305305488204665213841469519415116094330572703657595919530921861173819326117931051185480744623799627495673518857527248912279381830119491298336733624406566430860213949463952247371907021798609437027705392171762931767523846748184676694051320005681271452635608277857713427577896091736371787214684409012249534301465495853710507922796892589235420199561121290219608640344181598136297747713099605187072113499999983729780499510597317328160963185950244594553469083026425223082533446850352619311881710100031378387528865875332083814206171776691473035982534904287554687311595628638823537875937519577818577805321712268066130019278766111959092164201989380952572010654858632788659361533818279682303019520353018529689957736225994138912497217752834791315155748572424541506959508295331168617278558890750983817546374649393192550604009277016711390098488240128583616035637076601047101819429555961989467678374494482553797747268471040475346462080466842590694912933136770289891521047521620569660240580381501935112533824300355876402474964733

Roughly, anyway. But pi is irrational and can therefore not be exactly written down except as the pi symbol π. It has been calculated to over a trillion decimal places with no recurring sequence

Answer 8

exact "Pi" you talk about doesn't exist al we have is an estimate (but a very accurate one) this is because it is a irrational number
like for example the square root of 2.
at present we are up to 2 million figures

Answer 9

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.

It's value is 3.14 (generally used)

Answer 10

Pi is an irrational number. It means you cannot express in the form of P/Q, where P and Q are rational numbers

Decimals are another form of representation of P/Q form where P and Q are rational numbers.

The value of Pi is more than 3.14 but less than 3.15.
The value of Pi is more than 3.141 but less than 3.142.
The value of Pi is more than 3.1415 but less than 3.1416.

There is no end of saying like this.