Illustrating the Pythagorean Theorem by Squares

The triangle below is a right angle. The four quadrilaterals are squares.

Notice in the upper left corner where it shows the areas of the smaller squares whose side lengths are lengths of the triangle's legs.

Notice how the sum always equals the area of the largest square whose side length is the length of the triangle's hypotenuse.

Drag either Point A or Point B around. Does it continue to happen?

The original version of the Pythagorean Theorem was not written algebraically. It was stated geometrically.

Pythagoras wrote that the area of the square generated by the hypotenuse is the sum of the squares generated by the legs. You see that here numerically.

Darron Steele, Created with GeoGebra