A quick refresher: Pi is defined as the distance around a perfect circle, or the circumference, divided by the distance across it, or the diameter. It is also involved in calculating the area of a circle, the volume of a sphere, and many other mathematical formulas you might need in the sciences.
Conveniently, “pi” sounds like “pie,” and pies are round. You could celebrate Pi Day in a casual way by grabbing a slice of pastry, or pizza. If you’re in enrolled in school, your math class or math department might be doing something special already.
If you want to go where the day is said to be “invented,” look no further than San Francisco’s Exploratorium. Larry Shaw, who worked in the electronics group at the museum, began the tradition in 1988. Last year was Pi Day’s 25th anniversary there.