The perimeter of a circular flower bed is 31.4m, what is the area of the flower bed in square meters?
一个圆形花坛的周长是31.4m，这个花坛的面积是多少平方米？
<gadget id="calculator">2 * 3.14</gadget>
<output>6.28</output>

<gadget id="calculator">31.4 / 6.28</gadget>
<output>5</output>

<gadget id="calculator">5 ** 2</gadget>
<output>25</output>

<gadget id="calculator">3.14 * 25</gadget>
<output>78.5</output>

<result>78.5</result>