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Probability

Question
CBSEENMA9003675

The base radii of the two right circular cones of the same height are in the ratio 3 : 5. Find the ratio of their volumes.

Solution

Let the base radii of the two right circular cones be 3x and 5x respectively.
Let their common height be h. Then,
Volume of the first cone (v1) = 1 third πr squared straight h
                                          
                                          equals 1 third straight pi left parenthesis 3 straight x right parenthesis squared straight h
and, volume of the second cone (v2) = apostrophe 1 third πr squared straight h apostrophe
                                                      equals 1 third straight pi left parenthesis 5 straight x right parenthesis squared straight h
therefore   Ratio of their volumes
                            equals straight v subscript 1 over straight v subscript 2 equals fraction numerator begin display style 1 third end style straight pi left parenthesis 3 straight x right parenthesis squared straight h over denominator begin display style 1 third end style straight pi left parenthesis 5 straight x right parenthesis squared straight h end fraction
equals 9 over 25 equals 9 colon 25.