A semicircular flower bed is built in the community. The perimeter of this flower bed is 102.8 meters. What is its area in square meters?
小区内修了个半圆形花坛，这个花坛的周长是102.8米，它的面积是多少平方米？
<gadget id="calculator">102.8 / 5.14</gadget>
<output>20</output>

<gadget id="calculator">20 ** 2</gadget>
<output>400</output>

<gadget id="calculator">400 / 2</gadget>
<output>200</output>

<gadget id="calculator">3.14 * 200</gadget>
<output>628</output>

<result>628</result>