Question

Find the length of the side of a cube whose total surface area is $486c{m}^2$.

• A. 81 cm
• B. 486 cm
• C. 18 cm
• D. 9 cm

Answer 1

The correct option is D 9 cm

The total surface area of a cube is equal to $6a^2$, where $a$ is the side of the cube.
It is given that the total surface area of the cube is $486c{m}^2$.
So, $6a^2=486c{m}^2$
⇒ $a^2=81c{m}^2$
⇒ $a=9c{m}^2$
So, the length of the side of the cube is 9 cm