A bicycle has 36 front gears, 18 rear gears, and a wheel diameter of 5 decimeters. How many meters does the bicycle move forward per cycle?
一辆自行车前齿轮36个齿，后齿轮18个齿，车轮直径5分米．每蹬一圈自行车前进多少米．
<gadget id="calculator">1.57 * 2</gadget>
<output>3.14</output>

<result>3.14</result>