Kobayashi goes to school by bicycle every day. The outer wheel of the bicycle is directly 0.5 meters, and the wheels rotate about 80 times per minute. It takes 2 minutes to pass a bridge. How long is the bridge?
小林每天骑自行车上学．自行车的外轮直接是0.5米，车轮每分钟大约转80圈，通过一座大桥需要2分钟，这座大桥长多少米？
<gadget id="calculator">3.14 * 0.5 * 80 * 2</gadget>
<output>251.2</output>

<result>251.2</result>