Wang Laofu needs to make a cylindrical ventilation pipe with a section length of 12dm and a bottom diameter of 2dm. How many square decimeters of iron sheet are needed at least?
王老傅要做一节长是12dm，底面直径是2dm的圆柱形通风管，至少需要铁皮多少平方分米？
<gadget id="calculator">3.14 * 2 * 12</gadget>
<output>75.36</output>

<result>75.36</result>