what is the length. is the triangle similar .

Answer:
The triangle are similar and the missing line is 16.5
Step-by-step explanation:
The reason is because the scale factor is 2. You can find this out by multiply 8×2=16 and 9×2=18. With this in mind you divided 11 by 2 to get 5.5 for LD. Finally, adding 11+5.5 you will get 16.5.
Hope this helped