The diameter of a circular flower bed is 12 meters. Build a gravel road with a width of 1 meter around it. Find the area of the gravel road.
一个圆形花坛的直径是12米，在它的周围修一条宽1米的石子路，求石子路的面积．
<gadget id="calculator">12 / 2</gadget>
<output>6</output>

<gadget id="calculator">6 + 1</gadget>
<output>7</output>

<gadget id="calculator">7 ** 2</gadget>
<output>49</output>

<gadget id="calculator">3.14 * 49</gadget>
<output>153.86</output>

<gadget id="calculator">6 ** 2</gadget>
<output>36</output>

<gadget id="calculator">3.14 * 36</gadget>
<output>113.04</output>

<gadget id="calculator">153.86 - 113.04</gadget>
<output>40.82</output>

<result>40.82</result>