i dont think you can assume that it is a square and that x = 2*7 or that the horizontal segment is equal to the vertical segment
if you just consider looking at just one of the right triangles
it has a hypothenuse of 10, a side length of 7, and a missing side length that is x/2 (lets call it s for now)
pythagorean theorem
s^2 +7^2 = 10^2
solve for s
multiply by 2
then youll get x
