The perimeter of the base of a circular granary is 12.56 meters, how many square meters does it occupy?
一个圆形粮仓的底面周长是12.56米，它的占地面积是多少平方米？
<gadget id="calculator">2 * 3.14</gadget>
<output>6.28</output>

<gadget id="calculator">12.56 / 6.28</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>