Answer:
x=10
Explanation:
The triangles are similar, so their corresponding sides will be proportional. GF corresponds to NM, and GH corresponds to NO.
GF/ GH = NM / NO
6/9=x/15
Cross multiply
9*x=6*15
9x=90
Divide both sides by 9. This will get x by itself.
9x/9=90/9
x=10