Figure  3Can you visualize—picture   in  your    mind—what   the resulting   solid   looks   like?   It
can be  a   little  difficult   to  sketch  3-D geometry.   You may be  better  off if  you can
just    “see”   it  in  your    head.   It’ll   look    something   like    this.
It’s    a   cylinder    with    base    radius  3   and height  2.  So  now all you have    to  do  is
plug    r   =   3   and h   =   2   into    the formula:
If  the rectangle   in  Figure  3   is  rotated 360°    about   side     ,  what    is  the
volume  of  the resulting   solid?