Respuesta :

Area of the shaded part = 6 x 6 = 36 cm²
If you only need the area of the gray slice, that is side×side = 6×6 = 36 sq.cm
However if you need the whole surface area (SA) of the box, then that is:
SA = 4×side + 2×top = 4×6×5 + 2×6×6
SA = 120+72 = 192 sq.cm