To make a cylindrical ventilation pipe with a bottom diameter of 2dm and a length of 60dm, how much iron sheet is needed at least?
制作一节底面直径为2dm，长为60dm的圆柱形通风管，至少需要多少铁皮？
<gadget id="calculator">3.14 * 2 * 60</gadget>
<output>376.8</output>

<result>376.8</result>