Question

A cube and a square pyramid were joined to form the composite solid.

Answer 1

We know that
total surface area of the composite solid=surface area of the pyramid+surface area of the cube

surface area of the pyramid=4*area of lateral triangle side
area of lateral triangle side=12*9/2----> 54 in²
surface area of the pyramid=4*54---> 216 in²

surface area of the cube=5*[12*12]----> 720 in²

total surface area of the composite solid=216 in²+720 in²---> 936 in²

the answer is the option
936 square inches