There is a circular pool with a diameter of 8 meters. If a gravel road with a width of 2 meters is built beside the pool, what is the area of the gravel road in square meters?
有一个圆形水池直径是8米，如果在水池边修一条2米宽的石子路，求石子路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>