Question

The volume of a 1-metre iron rod is 1386 cubic centimetre. Find its diameter.

Answer 1

h=100cm
let diameter =d=2r.
=> $\pi r^{2} h$=1386
=>3.14 x r^{2}x100=1386
=> r^{2}=4.41
=> r=2.1
=>2r=d=4.2