Hi there!
First, we need to find the length of the stage. We can do this by plugging in our known values and solving for the unknown value.
WORK:
252 = 9 x l
l = 28
Next, we know that there are two lengths and two widths total. So all we need to do is to add two lengths plus to widths to find the perimeter.
WORK:
2(28) + 2(9) = P
56 + 18 = P
P = 74 feet^2
Hope this helps!! :)