A circular flower bed with a diameter of 20 meters is paved with a 2-meter-wide cement road around it. What is the area of the cement road in square meters?
一个直径是20米的圆形花坛，在它周围铺2米宽的水泥路面，这条水泥路的面积是多少平方米？
<gadget id="calculator">20 / 2</gadget>
<output>10</output>

<gadget id="calculator">10 + 2</gadget>
<output>12</output>

<gadget id="calculator">12 ** 2</gadget>
<output>144</output>

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

<gadget id="calculator">144 - 100</gadget>
<output>44</output>

<gadget id="calculator">3.14 * 44</gadget>
<output>138.16</output>

<result>138.16</result>