A proof of this theorem by President James A. Garfield involves the calculation of the area of a right trapezoid by different methods.
A proof of this theorem by President James A. Garfield involves the calculation of the area of a right trapezoid by different methods. Another common method of proving this theorem is by inscribing a square  at an angle inside of a larger square, and calculating area of the square both as a whole and as a sum of the component triangles and smaller square. A special case of the law of cosines, FTP name this theorem  describing the relationship between the length of the legs and the hypotenuse of a right triangle.
A proof of this theorem by President James A. Garfield involves the calculation of the area of a right trapezoid by different methods.
Pythagorean theorem