$\"\"$

Theorem of Pappus :

Let $\"\"$ be a region in a plane and and let $\"\"$ be the same plane such that $\"\"$ does not intersect with the interior of $\"\"$ .

If $\"\"$ is the distance between centeriod $\"\"$ and the line then the volume $\"\"$ of the solid of the revolution formed by revolving $\"\"$ about the line is $\"\"$ .

$\"\"$

The region is $\"\"$ .

Radius of the circle $\"\"$ .

Area of the circle is $\"\"$ .

Volume $\"\"$ of the solid of the revolution formed by revolving $\"\"$ about the line is $\"\"$ .

Here $\"\"$ is a distance between center of circle and $\"\"$ -axis.

Find the volume by substituting the values in the formula $\"\"$ .

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

$\"\"$

$\"\"$ .

$\"\"$

$\"\"$ .