A rectangle with a length of 8 cm and a width of 4 cm is rotated around the length of the rectangle to obtain a three-dimensional figure. What is the volume of the three-dimensional figure?
一个长方形的长8厘米，宽4厘米，以长方形的长为轴旋转一周得到一个立体图形，这个立体图形的体积是多少？
<gadget id="calculator">4 ** 2</gadget>
<output>16</output>

<gadget id="calculator">3.14 * 16 * 8</gadget>
<output>401.92</output>

<result>401.92</result>