The ratio of the circumference to the diameter of a circle is constant (namely, pi) and has been recognized for as long as we have written records.
A ratio of 3:1 appears in the following biblical verse: “And he made a molten sea, ten cubits from the one brim to the other: it was round all about, and his height was five cubits: and a line of thirty cubits did compass it about.” (I Kings 7, 23; II Chronicles 4, 2.)
The ancient Babylonians generally calculated the area of a circle by taking 3 times the square of its radius (=3), but one Old Babylonian tablet (from ca. 1900-1680 BC) indicates a value of 3.125 for pi.
Of course, there is humor in math, so here’s the joke of the day:
What is the official animal of Pi Day? Why, the pi-thon, of course!
Mathematically yours on the “mathy” day,