Question

Total surface area of a cube is 864 sq.cm. Find its volume.

Answer 1

Let the edge of the cube be l cm.

Total surface area of the cube = 864 cm²

∴ 6l² = 864 cm²

$$\begin{gathered} \Rightarrow l^2=\frac{864}{6}=144 \\ \Rightarrow l=\sqrt{144}=12\mathrm{cm} \end{gathered}$$
∴ Volume of the cube = l³ = (12)³ = 1728 cm³

Thus, the volume of the cube is 1728 cm³.