Since the cross section is constrained to be perpendicular to the base, the shape of it is constrained to be a ...
Rectangle
_____
That rectangle may be a square, but is not required to be.
The answer is (4n-5)(n-3)
A^2+B^2=C^2
48^2+12^2=C^2
2304+144=C^2
2448=C^2
now you keep this in radical form or you can round your answer.
Rounded=== 49.48=C
Radical==== 12√17=C
