Pi (3.14) is a very complicated number. It is thought that the ancient Babylonians discovered Pi in about 2000B.C. Some facts about Pi include:

• Pi is the ratio of the Circumference of a circle to the diameter.

• 2 Pi in radians form is 360 degrees. Therefore Pi radians is
  180 degrees and 1/2 Pi radians is 90 degrees.

• e raised to the i*pi power equals -1 (e is the base of the natural logarithm and i is the imaginary number which is the square root of -1)

•  Pi day is celebrated on March 14th at the explorium in San Francisco.

• All the digits of Pi can never be known

• Pi is an infinite number