The diameter of the rear wheel of the tractor is 1.2 meters, how many meters does the rear wheel move in one revolution?
拖拉机后轮的直径是1.2米，后轮转一周前进多少米．
<gadget id="calculator">3.14 * 1.2</gadget>
<output>3.768</output>

<result>3.768</result>