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 surface area of the three-dimensional figure?
一个长方形长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，这个立体图形的表面积是多少？
<gadget id="calculator">2 * 3.14 * 16</gadget>
<output>100.48</output>

<gadget id="calculator">100.48 + 200.96</gadget>
<output>301.44</output>

<result>301.44</result>