18 is what percent of 90

Question

How do i do this 

Answer 1

percentage=rate*base

percentage is the "is" number

base is the "of" number

rate is the "%"

18=rate*90

rate=18/90

rate=9/45=1/5 (or divide both terms by 18 if you didn't see this)

1/5=(1)(20)/(5)(20)=20/100=20%