A cylindrical biogas has a bottom radius of 4 meters and a depth of 2 meters. It is necessary to plaster the surrounding and bottom surface with cement. How many square meters is the area to be plastered with cement?
一个圆柱形沼气，底面半径是4米，深2米，要在周围与底面上抹上水泥，抹水泥的面积是多少平方米？
<gadget id="calculator">2 * 3.14 * 4 * 2</gadget>
<output>50.24</output>

<gadget id="calculator">4 ** 2</gadget>
<output>16</output>

<gadget id="calculator">3.14 * 16</gadget>
<output>50.24</output>

<gadget id="calculator">50.24 + 50.24</gadget>
<output>100.48</output>

<result>100.48</result>