Where does Pythagorean identity come from and how does it relate to right triangles

The Pythagorean identity is based from the three trigonometric identities that apply to the Pythagorean theorem. The three identities are founded on the concept that the hypotenuse is equal to the sum of the squares of the two sides of the right triangle. The identities can be determined through the substitution of sine and cosine in the right triangles measurements.