The proof is in pictures
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PROOF IN PICTURES
The pictures depict the successive stages of the proof of the Pythagorean theorem. The amount of red paint spent to cover the square built on the hypotenuse of a right triangle (Fig. 1) is exactly as much as it is required to cover the squares built on the legs of this triangle (Fig. 6). At figure 2 the square turned into a figure of equal size, the shape of filling an open book, which then moved upward.
The fact that the height of a right triangle extended to figure 3 by a dotted line falls at the point of intersection of the extended sides of the squares built on the legs requires justification - it is given on the second page of the cover.
In the following figures, the “kizhka” breaks up into parallelograms, and they turn into squares of equal size, built on the legs of a given right triangle. Thus, the sum of the areas of squares built on the legs of an arbitrary right triangle is equal to the area of the square built on its hypotenuse.
The Pythagorean theorem has been proven.