The master blacksmith has a rectangular iron sheet with a length of 12.56dm and a width of 9.42dm. He uses it to make the side of a cylindrical bucket. Now he needs to match a square iron sheet to make its bottom. At least a square iron sheet with an area of dm**2 is required.
铁匠师傅有一块长12.56dm，宽9.42dm的长方形铁皮，用它做一个圆柱形水桶的侧面，现在要配上一块正方形铁皮做它的底面，至少需要面积是多少dm**2的正方形铁皮．
<gadget id="calculator">12.56 / 3.14</gadget>
<output>4</output>

<gadget id="calculator">4 * 4</gadget>
<output>16</output>

<result>16</result>