Answer: 5.
Step-by-step explanation: If you convert 0.45 and 0.09 into whole numbers, (45 and 9) dividing them by each other gives you 5. Now, so you understand, if you take 0.09 and multiply it by 5, you get: 0.18, 0.27 0.36, 0.45. in order, just like how if you do the same with whole numbers, you get: 18, 27, 36, 45.
Hope this helps!