Aunt Wang used a 9.42-meter-long fence to surround a semicircular vegetable field. What is the area of the vegetable field in square meters?
王大妈用9.42米长的篱笆靠墙围一个半圆形的菜地，这个菜地的面积是多少平方米？
<gadget id="calculator">9.42 * 2</gadget>
<output>18.84</output>

<gadget id="calculator">18.84 / 3.14 / 2</gadget>
<output>3</output>

<gadget id="calculator">3 ** 2</gadget>
<output>9</output>

<gadget id="calculator">9 / 2</gadget>
<output>9/2 = around 4.5</output>

<gadget id="calculator">3.14 * (9/2)</gadget>
<output>14.13</output>

<result>14.13</result>