Question

180 of 37.5% of what number

Answer 1

180*100
18000/37.5
This equals 480

Answer 2

I think this is what you mean: "180 is 37.5% of what number" if so, this is my answer:
For these types of questions, I like using proportions... They just make life easier!!

180 37.5
------ = ---------
x 100

18000=37.5x

x=480
~Hope this helps~ ^^