If a rectangle has a length of 8 cm and a width of 4 cm and rotates it once about the length, what is the volume of the resulting cylinder?
一个长方形的长是8厘米，宽是4厘米，以长为轴旋转一周，形成的圆柱体的体积是多少立方厘米？
<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>