+23254 This is a box.
Assume that the length is 26, the width is 19.5, and the depth is 12.25.
There are 6 sides: front and back (which are equal, found by length·height), top and bottom (which are equal, found by length·depth), left side and right side (which are equal, found by height·depth).
The total surface area will be: TSA = 2·length·height + 2·length·depth + 2·height·depth
TSA = 2·26·19.5 + 2·26·12.25 + 2·19.5·12.25
Finish this to get the answer.
