To make a cylindrical chimney with a length of 1m and a diameter of 16cm, at least how many cm**2 iron sheets should be used.
做一节长1m，直径是16cm的圆柱形烟囱，至少要用多少cm**2的铁皮．
<gadget id="calculator">3.14 * 16 * 1 * 100</gadget>
<output>5_024</output>

<result>5_024</result>