A rectangular iron sheet with a length of 25.12 cm and a width of 18.84 cm can be used to make a cylindrical container with the largest volume when coupled with the following r = how many round iron sheets. (unit: cm)
用一块长25.12厘米，宽18.84厘米的长方形铁皮，配上下面r=多少圆形铁片正好可以做成一个容积最大的圆柱形容器．(单位：厘米)
<gadget id="calculator">25.12 / 3.14 / 2</gadget>
<output>4</output>

<result>4</result>