which statement explains the Pythagorean theorem
A. if a triangle is a right triangle then the sum of the squares of the longest leg and the hypotenuse is equal to the square of the third side
B. if all the angles in a triangle are of equal measure than the length of all sides will be equal
C. if a triangle is a right triangle then the sum of the square of the legs is equal to the square of the hypotenuse
D. if the interior angles of a triangle add up at 180 then the sum of the legs of the triangle is equal to the square of the hypotenuse