Question

The diameter of the sphere of the is $42cm.$ It is melted drawn into a cylindrical wire of $28cm$ diameter . Find the value of the length of the wire .

Answer 1

$\begin{array}{c}Given\\ diameterofasphere=42cm\\ radius=\frac{42}{2}=21cm\\ Now,\\ Volumeofsphere=\frac{4}{3}\pi r^3\\ =\frac{4}{3}\times \frac{22}{7}\times 21\times 21\times 21\\ =4\times 22\times 21\times 21\\ =3,8808c{m}^3\\ Volumeofsphere=volumeofcylinder\\ 38,808=\pi r^{2}h\\ \Rightarrow 38808=\frac{22}{7}\times 14\times 14\times h\\ h=\frac{696}{11}\\ h=63\\ Hence,lengthofwireis63cm.\end{array}$