Question

What is pi???

3.141592653

Answer 1

`pi` is an irrational number

Explanation:

There is a nice history of `pi`.

the Greeks more than 2000 years ago knew that the relationship between the length of a circle and its diameter was a constant number near to 3, but they don't know how to calculate it. Arquimedes (in the third century before Christ) realized that pi could be calculated by calculating circle surface area using polygons inscribed inside and found a relation used during centuries

`223/71`<`pi`<`22/7`

Nobody knows the exact value of `pi` in those days. But they know that `pi` is not a fraction, so `pi` is an irrational (that means `pi` has infinite decimal places without repeating any specific secuence of them).

You can see `pi` with billions of decimal places at several sites of internet. and with "only" 1500 decimal places at http://mimosa.pntic.mec.es/jgomez53/matema/conocer/pi_1500.htm

Answer 2

Pi `(pi)` is a constant that is the ratio of the circumference of a circle and its diameter.

Explanation:

Pi `(pi)` is a constant that is the ratio of the circumference of a circle and its diameter.

Pi is an irrational number, but is approximated as `3.14159`. Many sources simply use `3.14` for `pi`.

Answer 3

`pi` tells us how many times the diameter fits around the circumference of a circle.

The diameter divides into the circumference `pi` times.

`pi = C/D`

Explanation:

Mathematicians were always trying to find out how many times the diameter fits into the circumference of a circle.

If you try this for yourself with a piece of string and a circular object such as a mug or a pot or a bowl, you will find that the diameter fits around the circumference a bit more than `3` times.

You could say...." The diameter divides into the circumference `3` times, with a little bit left over."

The "little bit" is about `1/7`

Mathematicians found that no matter what size circle they used, the answer was always about `3 1/7`.

They called this value `pi`.

The diameter divides into the circumference `pi` times.

`pi` is an irrational number, which means it cannot be written as an a fraction and it cannot be determined exactly.

It is used in calculations as `22/7. 3.14, 3142` etc, depending on the accuracy required.

`pi = C/D`