The diameter of a circular flower bed is 8m, if the radius of the flower bed increases by 2m, how many square meters does the area of the flower bed increase?
一个圆形花坛的直径是8m，如果花坛的半径增加2m，花坛的面积增加多少平方米？
<gadget id="calculator">8 / 2</gadget>
<output>4</output>

<gadget id="calculator">4 + 2</gadget>
<output>6</output>

<gadget id="calculator">6 ** 2</gadget>
<output>36</output>

<gadget id="calculator">4 ** 2</gadget>
<output>16</output>

<gadget id="calculator">36 - 16</gadget>
<output>20</output>

<gadget id="calculator">3.14 * 20</gadget>
<output>62.8</output>

<result>62.8</result>