The perimeter of the circular flower bed in the street garden is 18.84 meters, find the area of the flower bed.
街心花园中圆形花坛的周长是18.84米，求花坛的面积．
<gadget id="calculator">2 * 3.14</gadget>
<output>6.28</output>

<gadget id="calculator">18.84 / 6.28</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>