Make four ventilating pipes with iron sheet, the length of each ventilating pipe is 6 decimeters, and the diameter of the bottom circle is 10 centimeters. How many square centimeters of iron sheet is needed at least?
用铁皮制作四节通风管，每节通风管的长是6分米，底面圆的直径是10厘米．至少需要铁皮多少平方厘米？
<gadget id="calculator">1_884 * 6</gadget>
<output>11_304</output>

<result>11_304</result>