9514 1404 393
Answer:
x = 1500
Explanation:
The right triangles are all similar, so the ratio of hypotenuse to short leg is the same for all.
x/900 = (1600+900)/x
x^2 = 900(2500) . . . . . . cross multiply
x = 30(50) . . . . . . . . . . . take the square root
x = 1500