[raverbashing]

> No one ever has told me in school that for all squares, the length of the diagonal equals The Square Root Of Two times the side of the square's

This is basic knowledge (and as someone said, comes from the Pythagorean theorem) and taught on school in a lot of places.

[paradoxparalax]

Yes, thats exactly what im saying, everyone knows the pythagorean theorem by memory, but something even more basic, a simple constant, not a formula, in a simple square, if you ask around, at least in my experience, no one knows.