Cdef is the inscribed square of RT triangle ABC, BC = 2, AC = 1, find the square cdef area

Cdef is the inscribed square of RT triangle ABC, BC = 2, AC = 1, find the square cdef area

You can set the side length of a square as X
Then △ EBF ∽ ACB can be proved by using two parallel lines
Then, de: BC = ad: AC takes several generations into X: 2 = (1-x): 1
The solution is x = 2 / 3
So the area of a square is 4 / 9