The radius of a circular hula hoop is 5 decimeters. If it advances 10 times on the horizontal plane, how many decimeters does the center of the circle move?
一个圆形呼啦圈的半径是5分米，它在水平面上前进10圈，则圆心平移了多少分米．
<gadget id="calculator">2 * 3.14 * 5 * 10</gadget>
<output>314</output>

<result>314</result>