The roller of a road roller is 1.5 meters long, and the radius of the bottom surface is 50 decimeters. If the roller of this road roller rolls for one revolution, how many square meters of the road surface will be pressed?
一台压路机的滚筒长1.5米，底面半径是50分米，这台压路机滚筒滚动1周，压过的路面是多少平方米？
<gadget id="calculator">50 / 10</gadget>
<output>5</output>

<gadget id="calculator">3.14 * 5 * 2 * 1.5</gadget>
<output>47.1</output>

<result>47.1</result>