If a solid piece of iron in the form of a cuboid of dimensions 49 cm x 33 cm x 24 cm, is moulded to form a solid sphere. Then, radius of the sphere is
(a) 21 cm
(b) 23 cm
(c) 25 cm
(d)19cm
(a) Given, dimensions of the cuboid = 49 cm x 33 cm x 24 cm
∴ Volume of the cuboid = 49 x 33 x 24 = 38808 cm3
$[\because$ volume of cuboid $=$ length $\times$ breadth $\times$ height $]$
Let the radius of the sphere is $r$, then
Volume of the sphere $=\frac{4}{3} \pi r^{3}$ $\left[\because\right.$ voulme of the sphere $\left.=\frac{4}{3} \pi \times(\text { radius })^{3}\right]$
According to the question,
Volume of the sphere $=$ Volume of the cuboid
$\Rightarrow \quad \frac{4}{3} \pi r^{3}=38808$
$\Rightarrow \quad 4 \times \frac{22}{7} r^{3}=38808 \times 3$
$\Rightarrow \quad r^{3}=\frac{38808 \times 3 \times 7}{4 \times 22}=441 \times 21$
$\Rightarrow \quad r^{3}=21 \times 21 \times 21$
$\therefore \quad r=21 \mathrm{~cm}$
Hence, the radius of the sphere is $21 \mathrm{~cm}$.