The radius of a circular flower bed is 3 meters. A gravel path with a width of 1 meter is paved around the flower bed. What is the area of the path in square meters?
一个圆形花坛的半径是3米，在花坛一周铺一条宽1米的碎石小路，小路的面积是多少平方米．
<gadget id="calculator">3 + 1</gadget>
<output>4</output>

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

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

<gadget id="calculator">16 - 9</gadget>
<output>7</output>

<gadget id="calculator">3.14 * 7</gadget>
<output>21.98</output>

<result>21.98</result>