Google homepage logo today honoring 'Pi Day', March 14

 

A few of you may be wondering, “What IS pi?” Rather than force you to dust off those brain cells that have atrophied since graduating college, pi is the ratio of the circumference to the diameter of a circle; approximately equal to 3.14159265358979323846264338327950288419716… the numbers following the decimal go off into infinity, so pi is usually simply rounded to 3.14. Hence, every March 14 (3/14) is National Pi Day. Google’s homepage logo illustrates some of the formulas that need pi.
The symbol for pi is of Greek origin and looks like this: Π