The front wheel of the road roller is cylindrical, the width of the wheel is 2m, and the diameter is 8dm. If the front wheel rotates once, what is the area of the road in m**2.
压路机的前轮是圆柱形，轮宽2m，直径8dm，前轮转动一周，压路的面积是多少m**2．
<gadget id="calculator">8 / 10</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">3.14 * (4/5) * 2</gadget>
<output>5.024</output>

<result>5.024</result>