If the master worker wants to make a cylindrical ventilation pipe with a bottom diameter of 30 cm and a length of 80 cm, how much iron sheet is needed at least?
工人师傅要制作一个底面直径是30厘米，长80厘米的圆柱形通风管，至少需要多少铁皮？
<gadget id="calculator">3.14 * 30 * 80</gadget>
<output>7_536</output>

<result>7_536</result>