Pi is the mathematical constant whose value is the ratio of any circle's circumference to it's diameter. Pi is represented by the numbers 3.14
http://answers.ask.com/Science/Mathematics/what_is...

1. Explain that pi is a mathematical constant equaling approximately 3.14159. 2. Write on a chalk board the derivation of pi: pi is equal to the circumference of a circle divided
http://www.ehow.com/how_7347731_teachpimath.html

Historically, Ancient Egyptians are the first who introduced a reasonably accurate value for the ratio of the circle area and its square radius. They used an approximate value of
http://wiki.answers.com/Q/What_is_the_history_of_p...

delicious the irrational number celebrated on march fourteenth of every year the area of a circle divided by the square of its radius
http://www.quora.com/Mathematics/Whatismathpim...
