I know that. I was just quoting the wizard of OZ movie line when the scarecrow received his brain.
The Scarecrow states an incorrect version of the Pythagorean theorem.
He states: "The sum of the square root of two sides of an isosceles triangle is equal to the square root of the third side."
There are two errors. The pythagorean theorem applies to right triangles, not isosceles. Also the theorem is that the squares of two legs equals the square of the hypotenuse.
Properly stated, "The sum of the squares of the two legs of a right triangle is equal to the square of the hypotenuse."
There.! Hopefully this is all summed up and squared up with ya legion.