What is Pi?

π is commonly defined as the ratio of a circle's circumference C to its diameter d.

It is given by
                            π=C/d

1. The ratio C/d is constant, regardless of the circle's size. For example, if a circle has thrice the diameter of another circle it will also have thrice the circumference. So, it will preserve the ratio C/d.
2. π is an irrational number, meaning that it cannot be written as the ratio of two integers.
3. Fractions such as 22/7 and 355/113 are commonly used to approximate π, but 22/7 and 355/113 are not the exact value of π. 
4. Because π is irrational, it has an infinite number of digits in its decimal representation, and it does not settle into an infinitely repeating pattern of digits.
5. π is a transcendental number, which means that it is not the solution of any non-constant polynomial equation with rational coefficients.