A fountain with a radius of 8m is surrounded by a cement road with a width of 1m. What is the area of this concrete road?
一个喷水池半径8m，周围有一条1m宽的水泥路．这条水泥路的面积是多少？
<gadget id="calculator">8 + 1</gadget>
<output>9</output>

<gadget id="calculator">9 ** 2</gadget>
<output>81</output>

<gadget id="calculator">3.14 * 81</gadget>
<output>254.34</output>

<gadget id="calculator">8 ** 2</gadget>
<output>64</output>

<gadget id="calculator">3.14 * 64</gadget>
<output>200.96</output>

<gadget id="calculator">254.34 - 200.96</gadget>
<output>53.38</output>

<result>53.38</result>