Pi is a mathematical constant that represents the ratio of a circle's circumference to its diameter. It is commonly approximated as 3.14, but it is an irrational number, meaning it cannot be expressed as a simple fraction and it has an infinite number of decimal places. The actual value of pi is approximately 3.1415926535897932384626433832795028841971693993751058209749445923078164062862089986280348253421170679... and so on.
