With just a string and a ruler you can quickly measure that pi must be just over three-and-an-eighth (3.125). With more precise measurements, you may be able to narrow it down to 3.14.
However, if you ask a typical maths nerd, you’ll get an earful of pi – 3.14159265 and so on. A surprising number of students have memorised 50 or even 100 digits after the decimal point.
The rough ratio of pi 3.14 gives us the date for Pi Day. March 14, or 3/14 in American dating style, makes sense for a celebration of this famous constant.
Coincidentally, Pi Day is also the birthday of Albert Einstein, who no doubt knew more than a little about pi. Pi Day celebrants, usually children with an enthusiastic teacher and a varying degree of personal interest in the subject, learn about pi, circles, and, if they’re lucky, eat baked pies of various sorts.