A once in a century event, at least for jurisdictions observing the MM-DD-YY
format (
see also), today—rendered as
9/16/25—illustrates the Pythagorean Theorem—that is, a²+b²=c² or three-squared plus four-squared equals five squared or the unit measures of the shorter vertices of any right triangle yield its
hypotenuse. As a bonus, the full year, 2025 (see above), is the square of forty-five. More auspicious dates with numerical properties at the links above.
