The perimeter of a semicircular part is 20.56 cm. Find the area of the semicircular part.
一个半圆形零件周长是20.56厘米，求这个半圆形零件的面积多少．
<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>

<result>25.12</result>