Question

If each edge of a cube is increased by $25\%$, what is the percentage increase in its surface area?

• A. $25\%$
• B. $48.75\%$
• C. $50\%$
• D. $56.25\%$

Answer 1

The correct option is D $56.25\%$

Let each edge of cube be $10$ units

Then, its surface area $=$ ${6a}^2=6\times {10}^2=600sq.units$

New edge $=10+25\%of10=12.5$ units

$\therefore$ New, surface area $=6\times {\left(12.5\right)}^2=937.5sq.units$

% increase $=\frac{937.5-600}{600}\times 100=56.25$%