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Probability

Question
CBSEENMA9003674

If the radius of the base of a right circular cone is halved keeping the height same, what is the ratio of the volume of the reduced cone to that of the original one?

Solution

 Let the radius of the base and the height of the original cone be r and h respectively.
∴ Volume of the original cone (v1)
             equals 1 third πr squared straight h space space space space space space space space space space space space space space space space space space space space space... left parenthesis 1 right parenthesis
For the reduced cone
Radius = straight r over 2
Height  = h
therefore  Volume of the reduced cone (v2)
            equals 1 third straight pi open parentheses straight r over 2 close parentheses squared straight h
equals space 1 fourth open parentheses 1 third πr squared straight h close parentheses equals 1 fourth straight v subscript 1 space space space space space space space space space space space space vertical line space From space left parenthesis 1 right parenthesis
therefore space space space straight v subscript 2 over straight v subscript 1 equals 1 fourth equals 1 space colon space 4
Hence, the ratio of the volume of the reduced cone to that of the original one is 1 : 4.