Let the lengths of right angles be a and b, and the length of hypotenuse be c.

The area of the small square = (a-b) 2 = 4. It means strength.

A small square and four surrounding triangles make a square. The area is equal to C 2.

c^2 = (a-b)^2 + 2ab = 4 + 3 X 4 = 16

c = 4