There is a 1-meter-wide path around a circular fish pond with a diameter of 40 meters. How many square meters of floor tiles should be laid on this path?
在一个直径40米的圆形鱼池周围有一条1米宽的小路，给这条小路铺上地砖，至少多少平方米的地砖？
<gadget id="calculator">40 + 1 + 1</gadget>
<output>42</output>

<gadget id="calculator">42 / 2</gadget>
<output>21</output>

<gadget id="calculator">21 ** 2</gadget>
<output>441</output>

<gadget id="calculator">3.14 * 441</gadget>
<output>1_384.74</output>

<gadget id="calculator">40 / 2</gadget>
<output>20</output>

<gadget id="calculator">20 ** 2</gadget>
<output>400</output>

<gadget id="calculator">3.14 * 400</gadget>
<output>1_256</output>

<gadget id="calculator">1_384.74 - 1_256</gadget>
<output>128.74</output>

<result>128.74</result>