"The sum of the square roots of any two sides of an isosceles triangle is equal to the square root of the remaining side"
Note: in reality, the scarecrow's statement was not even close to being true.
Here's one clarification I found...
"The sum of the "squares" (rather than "square roots") of "the shortest" (rather than "any") two sides of "a right angle" (rather than "an isosceles") triangle is equal to the "square" (rather than "square root") of the remaining side.
This is NOT the triangle inequalities theorem, rather it appears as merely a failed attempt at a watered down version of "Pythagoras' Theorem". "
Ha ha ha
Ho ho ho
And a couple of tra la las
That's the way we do the math
In the merry old land of Oz
;-)
-PJ