Find the surface area of a cube whose volume is

(i) Volume of the given cube $=343 \mathrm{~m}^{3}$

We know that volume of a cube $=(\text { side })^{3}$

$\Rightarrow(\text { side })^{3}=343$

i. e., side $=\sqrt[3]{343}=7 \mathrm{~m}$

$\therefore$ Surface area of the cube $=6 \times(\text { side })^{2}=6 \times(7)^{2}=294 \mathrm{~m}^{2}$

(ii) Volume of the given cube $=216 \mathrm{dm}^{3}$

We know that volume of a cube $=(\text { side })^{3}$

$\Rightarrow(\text { side })^{3}=216$

i. e., side $=\sqrt[3]{216}=6 \mathrm{dm}$

$\therefore$ Surface area of the cube $=6 \times(\text { side })^{2}=6 \times(6)^{2}=216 \mathrm{dm}^{2}$