Use 20.56 cm long iron wire to form a semicircle, what is its area in cm**2.
用20.56厘米长的铁丝围成一个半圆形，它的面积是多少厘米**2．
<gadget id="calculator">2 + 2</gadget>
<output>4</output>

<gadget id="calculator">4 ** 2</gadget>
<output>16</output>

<gadget id="calculator">16 / 2</gadget>
<output>8</output>

<gadget id="calculator">3.14 * 8</gadget>
<output>25.12</output>

<gadget id="calculator">25.12 / 2</gadget>
<output>12.56</output>

<result>12.56</result>