The radius of a motorcycle wheel is 30 cm, and the wheel rolls 100 times on the ground, how many meters does the car travel?
一辆摩托车车轮的半径是30cm，车轮在地上滚动100圈，车子前进了多少米？
<gadget id="calculator">100 / 100</gadget>
<output>1</output>

<gadget id="calculator">30 * 2 * 3.14 * 1</gadget>
<output>188.4</output>

<result>188.4</result>