The PI function is a Math & Trigonometry Function. Learn how to use the PI function in Excel, or how to multiply by PI, using this tutorial.

Today marks the 34th annual Pi Day. Researchers at NASA frequently use pi in their calculations while exploring the universe. Test your mathematical mettle with these Pi Day worksheets from NASA.

On March 14 mathematicians everywhere enjoy a slice of pie as they recite the digits of math's most famous constant. Pi, defined as the ratio between the circumference of a circle and its diameter ...