Kira made $180 for 12 hours of work. at the same rate, how much would she make for 9 hours of work?

She would make $135.
180/12=x/9
1620=12x
135=x

The easiest way to do this is by setting up a proportion, so

180 per every 12 hours of work = 180/12

and you want to know how much she would make for only 9 hours

(180 dollars/12 hours) = (x dollars/9 hours)

9 belongs on the bottom of your second fraction because you want it to be in the same place

from there you just solve the proportion; 180 divided by 12 is 15

15 = x dollars/9 hours

multiply both sides by 9

x = 135 dollars

so kira makes $135 in 9 hours of work