Unfortunately for you, that has indeed happened here. Now try Rule 1b: Divide first trig example by 2. Moving away from Flatland, the extreme upper value on surface of a sphere is 270°....Rule 1. The truth of a statement is in the statement, not who states it.

Eg. The sum of interior angles of a triangle are 360°, but not because Euclid said so.

(If he didn't say it, someone else would have.)...

And I believe Pythagoras not Euclid is associated with the correctly stated rule:

https://explorable.com/pythagoras