The front wheel of a road roller is 3 meters wide and 1 meter in diameter. If the front wheel rolls once, what is the area in square meters that passes over the road?
一台压路机的前轮宽3米，直径是1米，前轮滚动一周，压过路面的面积是多少平方米．
<gadget id="calculator">3.14 * 1 * 3</gadget>
<output>9.42</output>

<result>9.42</result>