Question

For a cube having a side $a$ units, its total surface area equals and its lateral surface area equals .

• A. $6a^2$ sq. units
• B. $4a^2$ sq. units
• C. $2a^2$ sq. units
• D. $8a^2$ sq. units

Answer 1

Answer: (A), (B)

$4a^2$ sq. units

Consider a cube as shown:

Let's draw the net of the cube too:

Now, its surface area is the sum of the areas of all the surfaces
$=a^2+a^2+a^2+a^2+a^2+a^2$
$=6a^2$ sq. units
And, similarly, the lateral surface area of a cube will be the sum of all areas excepting the top and the bottom.
$\therefore$ Lateral surface area of the cube
$=a^2+a^2+a^2+a^2=4a^2$ sq. units