A solid copper sphere of radius 9 cm is hammered and moulded into a wire of radius 2 cm. What is the length of this wire?

243 cm

The radius of the sphere =  9 cm

The radius of the wire = 2 cm. 

Volume of the wire = π × 2² × a

Volume of the sphere =\(\frac{4}{3}\) πR³ = \(\frac{4}{3}\) π(9)³

Let the length of the wire be a.

​According to the question,

π × 2² × a =  \(\frac{4}{3}\) π(9)³

= a = 243