Question

3 identical cubes are stacked on top of each other as shown in the diagram above, the combined surface area of the structure formed equals .

• A. $332$ sq. units
• B. $492$ sq. units
• C. $300$ sq. units

Answer 1

The correct option is A $332$ sq. units


Let $l,w\&h$ be the corresponding length, width, and height of one rectangular prism as shown above.
To find the total surface area of the structure, let's combine all three rectangular prisms into a single structure with dimensions as shown.
Here length $l=10$ units, width $w=4$ units and height $H=9$ units.
$\therefore$ Total surface area
$=2\times (l\times w+l\times H+H\times w)$
$=2\times (10\times 4+10\times 9+9\times 4)$
$=2\times (40+90+36)$
$=332$ sq. units