If the circumference of a circle is 6π cm, what is the circumference of half the circle in cm?
一个圆的周长是6π厘米，半个圆的周长是多少厘米．
<gadget id="calculator">3 * 3.14</gadget>
<output>9.42</output>

<gadget id="calculator">9.42 + 6</gadget>
<output>15.42</output>

<result>15.42</result>