Divide a circle with a radius of 12 cm into four parts, what is the arc length of each part in cm?
将半径为12cm的圆周平均分为四份，每一份的弧长为多少cm．
<gadget id="calculator">2 / 4</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">3.14 * 12 * (1/2)</gadget>
<output>18.84</output>

<result>18.84</result>