That’s either a nice example of hemibel thinking (http://libertycorner.blogspot.com/2004/07/hemibel-thinking.h...), of your memory going away, or of an extremely lousy education.

(You are of by a factor of 2)

I'm not sure sure if you made a mistake or if you are joking

The problem is exactly that the application of a formula requires some assumptions to be met, the first of which is logical consistency.

Try to draw a triangle such as the one mentioned.

There's a funny story. Before PISA, Finland looked up to the German school system, which was clearly considered superior by both sides.

When PISA came out in 2000, Finland was surprised to come out on top for Europe. Germany's performance in math was abysmal -- behind the US even. People started flocking to see what Finland did, and stopped looking up to Germany.

https://nces.ed.gov/pubs2002/2002116.pdf

The German school system has since gradually improved -- it's no longer behind the US -- but it's far from world-leading.