Let's verify each statements if they are true.
a.) The Pythagorean theorem applies to all right triangles.
TRUE - Pythagorean Theorem only works with right triangles.
b.) The hypotenuse is always the longest length of the right triangle.
TRUE - The hypotenuse is always the longest side in a right triangle because it is opposite of the largest angle, the ninety degree angle.
c.) The legs are always across from the 90° angle.
FALSE - The hypotenuse is always across from the 90° angle.
d.) The sum of the squares of the legs equals the square of the hypotenuse.
TRUE - we use this relationship as the Pythagorean Formula.
Therefore, the statement C is not a true statement,