A metallic sphere of radius 4.2 cm is melted and recast into the shape of a cylinder of radius 6 cm.

Let the height of the cylinder made be equal to h cm.

Its radius = 6 cm

Volume of the cylinder made = Volume of the given metallic sphere of radius 4.2 cm

$\Rightarrow \pi \times(6)^{2} \times \mathrm{h}=\frac{\mathbf{4}}{\mathbf{3}} \pi \times(4.2)^{3} \mathrm{~cm}^{3}$

$\Rightarrow 36 \times \mathrm{h}=\frac{\mathbf{4}}{\mathbf{3}} \times 4.2 \times 4.2 \times 4.2$

$\Rightarrow \mathrm{h}=\frac{\mathbf{4 . 2} \times \mathbf{4 . 2} \times \mathbf{4 . 2}}{\mathbf{3} \times \mathbf{9}} \mathrm{cm}=1.4 \times 1.4 \times 1.4 \mathrm{~cm}=2.744 \mathrm{~cm}$