A manfacturer drills a hole through the center of a metal sphere of radius
.
The radius of the hole is
.
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When we rotate a thin horizantal strip as shown in the figure about the
axis, we get a
resulting ring with inner radius
and outer radius
.
The width of the resulting ring is
.
Volume of the resulting ring is
.

Find volume integrate
to
.
The volume of the resulting ring is
.