# A lead pencil consists of a cylinder of wood with a solid cylinder of graphite filled in the interior. The diameter of the pencil is 7 mm and the diam

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A lead pencil consists of a cylinder of wood with a solid cylinder of graphite filled in the interior. The diameter of the pencil is 7 mm and the diameter of the graphite is 1 mm. If the length of the pencil is 14 cm, find the volume of the wood and that of the graphite.

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Volume of graphite=pir^2h
=22/7*(1/4)^2 140
=110mm^2
Total volume=piR^2h
=22/7*(7/2)^2*140
=5390mm^2
Volume of wood=total volume-volume of sphere
=5340-110mm^3
=5280mm^3.