Answer:
I believe your answer is 9
Explanation:
The way I found this answer was by assuming that triangle CDE was expanded to get triangle FGH. So I divided 18/4 and got the answer 4.5, which means that the triangle was expanded by a factor of 4.5. So I then multiplied the similar side to HG by 4.5 which was side ED. This got me with 4.5 x 2 and I got the answer 9.
Hope this helps! :)