“Secret name” says:
My philosophy teacher, who I do not know why he thinks he can do math, tried to prove Pythagoras theorem and drew that picture on the board. Then he said “It proves Pythagoras theorem because 3^2 + 4^2 = 5^2, as shown in the picture”. Then I said I had not understood why it proves Pythagoras theorem.
He asked to the class if someone else had not understood and they did not said anything. Then he said (not with those words) I am stupid and the prove was trivial.
Thanks to “secret name” for this submission.
[[Editor’s note: Unfortunately this happens all too often when a teacher does not know an answer. But don’t let it be a reason to discourage you from math!]]