Instruction: What is Pythagorean or Pythagoras' Theorem

Response: Pythoagorean theorem is an euclidian theorem attributed to a Greek philosopher from around 570 BC named Pythagoras. 
The Pythagorean theorem states that for a right angled triangle, the sum of the squares of the two adjacent sides is equal to the square of the hypotenuse (the side opposite to the right angeled triangle).