A circular flower bed with a diameter of 20 meters, how many square meters does it cover?
一个直径20米的圆形花坛，它的占地面积是多少平方米？
<gadget id="calculator">20 / 2</gadget>
<output>10</output>

<gadget id="calculator">10 ** 2</gadget>
<output>100</output>

<gadget id="calculator">3.14 * 100</gadget>
<output>314</output>

<result>314</result>