There is a circular flower bed with a diameter of 20 meters in the park. Now it is necessary to build a path with a width of 1 meter along the periphery of the flower bed. Find the area of the path.
公园有一个直径是20米的圆形花坛，现在要沿花坛外围修一条宽1米的小路，求小路的面积．
<gadget id="calculator">20 / 2</gadget>
<output>10</output>

<gadget id="calculator">10 + 1</gadget>
<output>11</output>

<gadget id="calculator">11 ** 2</gadget>
<output>121</output>

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

<gadget id="calculator">121 - 100</gadget>
<output>21</output>

<gadget id="calculator">3.14 * 21</gadget>
<output>65.94</output>

<result>65.94</result>