Answer:
SA = 578ft²
Explanation:
First, we have to know the formula of finding the surface area of a rectangular prism.
Formula: 2(wl + hl + hw)
w = width l = length h = height
Next, we separate the composite figure into two rectangular prisms.
Since we have all measurements, let's use that to find the SA.
The first shape (to the left)
SA = 2(wl + hl + hw)
SA = 2(4 x 9 + 9 x 9 + 9 x 4)
SA = 2(36 + 81 + 36)
SA = 2(153)
SA = 306
Then, we do the other shape(to the right)
We know the measurement of length = 4 because it is the same measurement as the width
SA = 2(wl + hl + hw)
SA = 2(4 x 4 + 15 x 4 + 15 x 4)
SA = 2(16 + 60 + 60)
SA = 2(136)
SA = 272
Lastly, we add those two
306 + 272 = 578
Therefore, SA = 578ft²
sorry if Im wrong