Take a rectangular iron sheet with a length of 18.84 decimeters and a width of 12.56 decimeters to make the side of a bucket without a lid. To make the volume of the bucket the largest, at least a bottom surface of how many square decimeters is required.
把一张长18.84分米，宽12.56分米的长方形铁皮，做一个无盖水桶的侧面，要使水桶容积最大至少需要配一个多少平方分米底面．
<gadget id="calculator">18.84 / 3.14 / 2</gadget>
<output>3</output>

<gadget id="calculator">3 ** 2</gadget>
<output>9</output>

<gadget id="calculator">3.14 * 9</gadget>
<output>28.26</output>

<result>28.26</result>