Pythagorean theorem
in the right angled triangles there is a relationship that governs the length of the three sides. if he knows the length of any two sides, the third side may be calculated by the use of the Pythagorean theorem.
this theorem states that the square on the hypotenuse of a right angled triangle is equal to the sum of the squares on the remaining two sides.
in Pythagorean theorem we only use to find a length of the missing side of a right angle triangle only.