$\"\"$

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Height of the cone is $\"\"$ radius of the base is $\"\"$ .

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Cone is cut by a plane parallel to base and $\"\"$ units above the base.

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Thus, the rotation is vertical.

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Draw diagram for the situation:

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$\"\"$

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The volume of the solid generated revolving about the $\"\"$ -axis.

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Washer method: $\"\"$ .

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Find $\"\"$ .

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The points are $\"\"$ and $\"\"$ .

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Line joining the points $\"\"$ and $\"\"$ is

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$\"\"$

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$\"\"$

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$\"\"$

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$\"\"$

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Here $\"\"$ and $\"\"$ .

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Integral limits are $\"\"$ and $\"\"$ .

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$\"\"$

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$\"\"$ .

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Substitute $\"\"$ , $\"\"$ and $\"\"$ , $\"\"$ .

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$\"\"$

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$\"\"$

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$\"\"$ .

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$\"\"$

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$\"\"$ .