USA TODAY — On Friday, millions of people worldwide will celebrate both a mathematical constant and a sweet filling in a wheaten crust. In other words—Pi Day.

Pi is the ratio used to compute the circumference, area, and volume of circles.

Recommended Stories

Too many kids are dying in gun accidents. The NRA has a program to save them

Study: Trigger warnings actually hurt trauma survivors

Poll: 80% of philosophy students embrace socialism

For those who didn’t memorize it in middle school, that works out to 3.141592653 for the first ten digits.