A copper sphere of diameter 18 metre is drawn into a cylindrical wire of length 12 metre. What is the radius of the wire?

9 metre

We know that,

Volume of sphere = \(\frac{4}{3}\) πr³

Volume of cylinder = πr²h

We have,

Radius of sphere = 9 cm

Radius of wire = 0.3 cm

Now,

Volume of sphere = Volume of cylinder

= \(\frac{4}{3}\) πr³= π0.3²h

= \(\frac{4}{3}\) × 729 = 0.3²h

= 4 × 243 = 0.09h

Length = h = 10800 cm = 108 m