A walkway with a width of 2 meters is built around a circular flower bed with a diameter of 8 meters. What is the area of the walkway in square meters?
在一个直径8米的圆形花坛周围修一条宽2米的走道，走道的面积是多少平方米．
<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>