A certain factory has a cylindrical tin chimney with a bottom diameter of 6 decimeters and a height of 25 decimeters. If the chimney is to be raised to 30 decimeters, how many square decimeters of iron sheet is needed at least?
某工厂有一根圆柱形铁皮烟囱，底面直径是6分米，高是25分米，现要将烟囱加高到30分米，至少还需要铁皮多少平方分米？
<gadget id="calculator">3.14 * 6 * 30</gadget>
<output>565.2</output>

<result>565.2</result>