The correct statement that identifies Hank's error is:
He did not set up the Pythagorean Theorem correctly. The hypotenuse should be isolated on one side of the equation.
In the context of the Pythagorean theorem, \( a^2 + b^2 = c^2 \), Hank needs to ensure that he correctly sets up the equation to isolate \( c^2 \) as the sum of the squares of the legs of the triangle (not simply manipulating constants).