The circular flower bed in the park in the middle of the street has a circumference of 15.7 meters. What is the area of the flower bed in square meters?
街心公园里的圆形花坛，周长15.7米．花坛占地面积是多少平方米．
<gadget id="calculator">15.7 / 3.14 / 2</gadget>
<output>2.5</output>

<gadget id="calculator">2.5 ** 2</gadget>
<output>6.25</output>

<gadget id="calculator">3.14 * 6.25</gadget>
<output>19.625</output>

<result>19.625</result>