Question

Where did the simple for Pi come from/how did it come about?

Answer 1

Symbol for pi (π ) is a letter in the Greek alphabet. π is equivalent to "p" in the English language. By definition, π is the ratio of the Circumference of a circle to its Diameter. Circumference can be thought of as the perimeter of a circle. That could be the connection as to why π was chosen.

http://www.businessballs.com/greekalphabet.htm