Draw a circle with a compass. If the distance between the toes of the compass is 3 cm, what is the circumference of the circle in cm?
用圆规画一个圆，如果圆规两脚尖之间的距离是3cm，这个圆的周长是多少cm．
<gadget id="calculator">2 * 3.14 * 3</gadget>
<output>18.84</output>

<result>18.84</result>