Question

Total surface area of a cube is 5400 sq. cm. Find the surface area of all vertical faces of the cube.

Answer 1

Let the edge of the cube be l cm.

Total surface area of the cube = 5400 cm²

$$\begin{gathered} \therefore 6l^2=5400 \\ \Rightarrow l^2=\frac{5400}{6}=900 \\ \Rightarrow l=\sqrt{900}=30\mathrm{cm} \end{gathered}$$
∴ Surface area of all vertical faces of the cube = 4l² = 4 × (30 cm)² = 4 × 900 cm² = 3600 cm²

Thus, the surface area of all vertical faces of the cube is 3600 cm².