9514 1404 393
Answer:
12 units
Step-by-step explanation:
In this geometry, all of the right triangles are similar, so corresponding sides are proportional.
short-side/short-side = long-side/long-side
9/x = x/16
x^2 = 144 . . . . cross multiply
x = 12 . . . . . . . take the square root
