A semicircular flower bed has a perimeter of 10.28 meters, what is the area in square meters?
一个半圆形花坛，周长为10.28米，面积为多少平方米？
<gadget id="calculator">4 / 2</gadget>
<output>2</output>

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

<gadget id="calculator">3.14 * 2</gadget>
<output>6.28</output>

<result>6.28</result>