A circle with a radius of 10 cm rolls on the ground 10 times, how far does its center move?
一个圆半径10厘米，在地上滚动10周，它的圆心移动了多少距离？
<gadget id="calculator">2 * 3.14 * 10 * 10</gadget>
<output>628</output>

<result>628</result>