Explanation:
A sector of a circle with radius 5 cm will look something
like this.
When recast into a right-circular cone of height 4 cm it
will look something like this.
Hence, the radius of the sector becomes the slant height of
the cone. Therefore,
Base radius of the cone (r) = Ö(l2
– h2)
Hence r = 3 cm.
Volume = (1/3)*pi*r2*h
= 12*pi
cm3