$\"\"$

The volume of a sphere is $\"\"$ .where r is radius of sphere.

$\"\"$

The radius is half of its diamter, $\"\"$ .

$\"\"$ $\"\"$

$\"\"$ (Substitute 0.9 for r)

$\"\"$ (Evaluate powers: $\"\"$ )

$\"\"$ . (Multiply: $\"\"$ )

$\"\"$ . (Divide: $\"\"$ ) $\"\"$

$\"\"$ (Substitute 3.14 for $\"\"$ )

$\"\"$ (Multiply: $\"\"$ ) $\"\"$

The volume of the sphere is $\"\"$ .