Uncle Zhang formed a semicircular sheepfold with a 25.7-meter-long fence. What is the area of the sheepfold in square meters?
张伯伯用25.7米长的篱笆围成了一个半圆形的羊圈．这个羊圈的面积是多少平方米？
<gadget id="calculator">25.7 / 5.14</gadget>
<output>5</output>

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

<gadget id="calculator">25 / 2</gadget>
<output>25/2 = around 12.5</output>

<gadget id="calculator">3.14 * (25/2)</gadget>
<output>39.25</output>

<result>39.25</result>