The drum of the road roller is a cylinder. Its cross-sectional circumference is 3.14 meters and its length is 2.5 meters. How much road surface can it press every time it rolls? If it turns 20 times, how big is the road that has been pressed?
压路机的滚筒是一个圆柱形，它的横截面周长是3.14米，长是2.5米，每滚一周能压多大的路面？如果转20周，压过的路面有多大？
<gadget id="calculator">3.14 * 2.5 * 20</gadget>
<output>157</output>

<result>157</result>