Pythagoras’ theorem states that for a right angled triangle, if a square was to be drawn on each side of the triangle, the area of the square on the hypotenuse side (the side opposite the 90° angle), is equal to the sum of the area of the two squares drawn on the other two sides.
Where, a, b and c are the sides of the triangle.
Pythagoras’ Theorem is most often employed to find the length of an unknown side of a triangle, and as such the form:
a2 + b2 = c2
is most frequently used.