The roller of a road roller is a cylinder, its length is 1.5 meters, and the radius of the roller is 0.5 meters. If it rolls 15 times per minute, how many square meters can be rolled per hour?
一种压路机的滚筒是圆柱体，它的长是1.5米，滚筒的半径是0.5米，如果每分钟滚15周，每小时可以压路多少平方米？
<gadget id="calculator">3.14 * 2 * 0.5 * 1.5</gadget>
<output>4.71</output>

<gadget id="calculator">4.71 * 15 * 60</gadget>
<output>4_239</output>

<result>4_239</result>