Answer:
h=7.5 in
Explanation:
see the attached figure with letters to better understand the problem
In the right triangle ABC
sin(CAB)=15/18 ----> opposite side divided by the hypotenuse
In the right triangle CDE
sin(DCE)=h/9 ----> opposite side divided by the hypotenuse
In this problem
∠CAB=∠DCE ------> by corresponding angles
therefore
sin(CAB)=sin(DCE)
15/18=h/9
solve for h
h=15*9/18
h=7.5 in