Question

What is the surface area of a cube of side 15cm?

Answer 1

Hint- In order to solve this problem, we will use the formula of surface area of a cube, because in this question the side of a cube is given. Formula of surface area of the cube is given as $6{a^2}$ where “a” is the side of a cube.

Complete step-by-step answer:
We will solve the problem with the help of a given diagram.

Given that side of a cube is 15cm
Let “a” be the side of a cube
We know that surface area of cube $6{a^2}$
Where a is the side of cube
Substitute the value of a = 15cm in the above formula, we get
Surface Area:
$
   = 6{a^2} \\
   = 6{\left( {15} \right)^2}{\text{ }}\left[ {\because a = 15cm} \right] \\
   = 6 \times 15 \times 15 \\
   = 1350c{m^2} \\
 $
Hence, the surface area of a cube of side 15 cm is $1350c{m^2}$.

Note- This problem can also be solved by the use of figure, first finding the area of each face and finally adding all the areas together. But for such common figures like cube and cuboid, students must remember the surface area of these figures to directly find the answer.