March 14 is Pi Day, a day to celebrate one of the most used mathematical constants. Pi is defined as the ratio of a circle’s circumference to its diameter. Since the first three digits of Pi are 3.14, Pi Day is observed on March 14. Today in the Upper School, students celebrated the return of Rivalry Week, a week-long friendly competition between grades. The day started with the Amazing Race, a relay race featuring many activities throughout the length of the Upper School campus, and then students gathered for a more cerebral challenge—which grade could recite the most digits of pi? Tenth-grader Brendan P. ’24 bested the incredibly impressive field. The day’s excitement also included an edible element. Because who doesn’t want a slice of π, er, pie?