Q19 of 49 Page 1

A solid cone of base radius 10 cm is cut into two parts through the mid-point of its height, by a plane parallel to its base. Find the ratio in the volumes of the two parts of the cone.


Let the height of the cone be H m


Radius of the frustum = R = 10 cm


After cutting, the new height of the cone = m


Let the new radius of the cone be r cm


⸫ r = = 5 cm [⸪ the cut has been made at the midpoint of the cone]


Volume of the new cone = πr2h


=


Volume of the frustum =


=


=


=


⸫ Ratio of the two volumes =


= 1: 7


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