ANSWER:
In the development of the step by step, you will find the detailed answer
Explanation:
We have the following triangle, which is made up of two other triangles:
If the triangle ABC is right, then:

The triangle ABC and the triangle DBC by the similar triangles theorem, which says:
If the height corresponding to the hypotenuse is plotted in a right triangle, the two triangles formed are similar to each other, and similar to the given triangle.
Therefore:

If we add we would be:

In this way, using the similarity between the triangles ABC and DBC, we arrive at what is the Pythagorean theorem.