help me with this please pleaseee!

Answer:
2
Step-by-step explanation:
Since the two rectangles are similar, the ratio of their similar sides will be a constant k
Hence;
18/9 = 12/6 = k
Since they are all the same, then;
k = 18/9
k = 2
Hence the scale factor is 2
Answer:
Step-by-step explanation:
The scale factor is the ratio of corresponding sides:
or
Correct choice is D