In a rectangular open space with a length of 16 meters and a width half of the length, build a semicircular flower bed as large as possible. What is the area of the flower bed?
在一块长16米，宽是长一半的长方形空地，修一个尽量大的半圆形花坛，这个花坛的面积是多少？
<gadget id="calculator">16 / 2</gadget>
<output>8</output>

<gadget id="calculator">8 ** 2</gadget>
<output>64</output>

<gadget id="calculator">64 / 2</gadget>
<output>32</output>

<gadget id="calculator">3.14 * 32</gadget>
<output>100.48</output>

<result>100.48</result>