The radii of the internal and external surfaces of a metallic spherical shell are 3 cm and 5 cm respectively. It is melted and recast into a solid right circular cylinder of height 10 cm. Find the diameter of the base of the cylinder.
A solid metallic sphere of diameter 21 cm is melted and recast into a number of smaller cones each of diameter 7 cm and height 3 cm. Find the number of cones so formed.
The volume of the metal in the metallic spherical shell
Let the diameter of the base of the cylinder be r cm.
Since the volume of the hollow spherical shell will be equal to the volume of the cylinder casted.
r = 7
Hence, the diameter of the base of the cylinder is 7 cm.
Let n be the number of cones formed.
Volume of sphere = volume of n cones
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