1/4”=15’
Convert 9 to 36/4 for easier math.
36/4 divided by 1/4 flip the second fraction and multiply for easy math
36/4 x 4/1 = the denominator 4 of the first fraction cancels out with the numerator 4 of the second so you get 36/1 or just 36.
Now that we have that number, multiply it by the original 15.
36x15=540