The tablet is the earliest discovered example of applied geometry. When you purchase through links on our site, we may earn an affiliate commission. Here’s how it works. A 3,700-year-old clay tablet ...

Once a century, a very special day comes along. That day is today — 9/16/25. Pi Day (3/14) often comes with sweet treats; Square Root Day (4/4/16 or 5/5/25, for example) has a certain numerical rhyme.

MOST READERS will have encountered Pythagoras’s theorem about right-angled triangles—that the square on the hypotenuse is equal to the sum of the squares on the other two sides—at school. But the less ...