Pythagoras and trigonometry are both important areas of mathematics. Pythagoras' theorem relates the sides of a right triangle, stating that the square of the hypotenuse is equal to the sum of the squares of the other two sides. Trigonometry builds on Pythagoras' theorem by defining trigonometric functions that allow relationships between the sides and angles of triangles to be quantified and generalized to any triangle, not just right triangles.