The length of the wire of 0.2 mm radius that can be drawn after melting a solid copper sphere of diameter 18 cm, is?

Radius of sphere = 9 cm
Volume of sphere = [ 4/3 x π x (9)³] cm³ = 972π cm³
Radius of wire = 0.2 mm = 2/(10 x 10) cm = 1/50 cm
Let the length of wire be = L cm
Then, 972π = π x (1/50)² x L
⇒ L = (972 x 50 x 50 ) cm
∴972π = π x (1/50)² x L
⇒ L = (972 x 50 x 50) cm
∴ Length of wire = (972 x 50 x 50)/100 m = 24, 300 m