A rectangular box has length $9\text{ cm}$, breadth $4\text{ cm}$ and height $7\text{ cm}$. Find its total surface area.

Step-by-step solution

1. Use the formula for total surface area of a rectangular box: $S=2(lb+bh+lh)$.
2. Compute the face areas: $lb=9\times 4=36{\text{ cm}}^2$, $bh=4\times 7=28{\text{ cm}}^2$, $lh=9\times 7=63{\text{ cm}}^2$.
3. Sum the three face areas: $36+28+63=127{\text{ cm}}^2$.
4. Multiply by 2: $2\times 127=254{\text{ cm}}^2$.
5. So the total surface area is $254{\text{ cm}}^2$.

Concept tested: Surface area of rectangular box

Published 10 October 2026 · How this solution was prepared and checked