# What is the exact value of #pi#?

##### 2 Answers

Oct 18, 2015

Oct 18, 2015

It is not expressible as a fraction, terminating or repeating decimal.

#### Explanation:

For example:

#pi = 4 * tan^(-1)(1) = 4 * (1-1/3+1/5-1/7+1/9-1/11+...)#

There are some useful rational *approximations* for

For example

or of course, decimal approximations: