The outer diameter of a bicycle tire is 50 cm. If it rotates 100 times per minute on average, it takes 15 minutes for the bicycle to cross a bridge. Ask: How long is this bridge in meters?
一辆自行车轮胎的外径是50厘米，如果平均每分钟转100周，骑该车通过一座桥需15分钟，问：这座桥长多少米？
<gadget id="calculator">50 / 100</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">100 / 10</gadget>
<output>10</output>

<gadget id="calculator">3.14 * (1/2) * 10 * 15</gadget>
<output>235.5</output>

<result>235.5</result>