Answer
See explanations.
Work Step by Step
There are four errors in the Scarecrow’s statement that do not agree with the Pythagorean Theorem $a^2+b^2=c^2$
1. It should be the the sum of squares, not square roots;
2. It should be the legs, not any two sides;
3. It should be in a right triangle, not just isosceles;
4. It should be the square of the hypotenuse, not the square root of the remaining side.