Determine the dimensions of a rectangular solid (with square base) with a maximum volume if its surface are is 337.5 square centimeters.

The question is asking to determine the dimension of a rectangular solid with a maximum volume if its surface area is 337.5 square centimeters and base on my further computation, I would say that the answer would be x= sqrt 56.25 and y = 7.5 and having a maximum volume of 421.875. I hope this would help 

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