I'll give you brainliest me. this diagram shows a smaller square inscribed within a larger square.
answer with supporting work:

Each side of the smaller square is the hypotenuse of the triangles with legs of 3 and 4.  From the Pythagorean Theorem, we can calculate the hypotenuse:
hypotenuse^2 = 3^2 + 4^2
hypotenuse^2 = 9 + 16
hypotenuse^2 = 25
hypotenuse = 5
Therefore, the area of the smaller square is 5 * 5 = 25