The number 3 is associated with self-achievement, creativity, self-expression, and things coming full circle. Because 3 is a number of completion as well as creation, it's closely associated with ...

Today is Pi Day, but you should stop celebrating it and instead use tau as your circle constant. Tau Day — the true holiday — is celebrated on June 28th.

The holiday has gotten such recognition that in March 2009, the U.S. House of Representatives designated March 14 as Pi Day. MORE: Indiana once tried to define Pi as 3.2.The bill almost passed.

Known around the world as "Pi Day," it’s a time to celebrate one of mathematics' most famous constants: Pi, the ratio of a circle's circumference to its diameter, approximately 3.1415.