A sector of a circle of radius 5 cm is recast into a right circular cone of height 4 cm. What is the volume of the cone so formed?

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) =

Hence, r = = 3 cm.

Volume = (1/3)*pi*r2*h

= 12*pi cm

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dhanush says

January 15, 2013 at 2:57 amhey doesnt it depend on the angle of the sector..??..the area itself may vary..!!!!