A second hand is 3 centimeters long, what is the distance traveled by its tip in decimeters when it makes two revolutions?
一根秒针长3厘米，它的针尖转动两周所行的路程是多少分米．
<gadget id="calculator">2 / 10</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">3.14 * 3 * 2 * (1/5)</gadget>
<output>3.768</output>

<result>3.768</result>