The radius of the wheel of a car is 0.5 meters, how many meters does the car travel when the wheel rotates 100 times?
一辆汽车的车轮半径是0.5米，车轮转动100圈，汽车前进多少米．
<gadget id="calculator">2 * 3.14 * 0.5 * 100</gadget>
<output>314</output>

<result>314</result>