The radius of the circle where an arc is located is 9 cm, and the central angle subtended by the arc is 60°, what is the length of this arc in cm?
一段弧所在的圆的半径为9厘米，弧所对的圆心角为60°，那么这段弧的长为多少厘米．
<gadget id="calculator">60 / 360</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">3.14 * 2 * 9 * (1/6)</gadget>
<output>9.42</output>

<result>9.42</result>