September 16, 2025, is the only date that fits the definition this century. Here’s the specific math to add it all up: 3 multiplied by itself is 9, 4 squared is 16, and 5 squared is 2025. On top of ...

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 ...

NPR's Ailsa Chang talks with Regina Barber and Emily Kwong of Short Wave about the oldest known tadpole, new proofs of the Pythagorean Theorem, and the evolutionary roots of alcohol consumption. All ...

Two high school students proved the Pythagorean theorem in a way that one early 20th-century mathematician thought would be impossible: by using trigonometry. Calcea Johnson and Ne’Kiya Jackson, both ...

Pythagorean Triple Square Day, as one man affectionately calls 9/16/25, is a day like no other this century. On 9/16/25, celebrate a date of mathematical beauty Once a century, a very special day ...