The radius of a circular flower bed is 2 meters, what is the area of the flower bed in square meters?
一个圆形花坛的半径为2米，这个花坛的面积是多少平方米？
<gadget id="calculator">2 ** 2</gadget>
<output>4</output>

<gadget id="calculator">3.14 * 4</gadget>
<output>12.56</output>

<result>12.56</result>