What is pie in circle?

Answer 1

Firstly the word is pi. It is a Greek letter.

In mathematics it is often useful to use letters to represent something unknown. We often use the letter x or the letter n to do so.

In certain special cases we keep a letter and that represents something so we all know what we are referring to.

In this case, pi.

Pi refers to the ratio of the diameter of a circle to its circumference. It is always the same. No matter what size the circle the diameter will always be a certain size compared to the circumference.

It is often useful to keep and use such letters and phrases. It is a kind of shorthand for people that use mathematics.

Answer 2

In mathematics, pi (π) is a mathematical constant that represents the ratio of a circle's circumference to its diameter. It is an irrational number, meaning it cannot be expressed as a finite decimal or a fraction. The value of pi is approximately 3.14159.