Answer:
KJH
Explanation:
similar triangles have the same angles
The angle FHG is the same as JHK
The angle GFH is the same as HKJ
and the angle GHF is the same as HJK
(I forgot the names of the theorems that prove this but it's true)
Because of this you want the letters to match up,
For FGH, the F will be replaced by K, G with J, and H remains H
so you get KJH