It is known that the radius of the wheel of the bicycle is 4 decimeters, and the wheel rolls 200 times, then how many meters is the distance traveled by the bicycle.
已知自行车的车轮半径是4分米，车轮滚动200周，那么自行车走过的路程是多少米．
<gadget id="calculator">4 / 10</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">2 * 3.14 * (2/5) * 200</gadget>
<output>502.4</output>

<result>502.4</result>