The circumference of the bottom of a cylinder is 12.56dm, what is the bottom area of the bucket?
一个圆柱底面周长是12.56dm，这个水桶的底面积是多少？
<gadget id="calculator">12.56 / 3.14 / 2</gadget>
<output>2</output>

<gadget id="calculator">2 ** 2</gadget>
<output>4</output>

<gadget id="calculator">3.14 * 4</gadget>
<output>12.56</output>

<result>12.56</result>