Ningbo Rail Transit Line 1 is an east-west main line. The first phase of the line is about 20.9 kilometers long. On the map with a scale of 1:10000, how many cm is its length.
宁波轨道交通一号线为东西向主干线，一期线路长约20.9公里，在1：10000的比例尺的地图上，它的长约多少cm．
<gadget id="calculator">1 / 10_000</gadget>
<output>1/10_000 = around 0.0001</output>

<gadget id="calculator">2_090_000 * (1/10_000)</gadget>
<output>209</output>

<result>209</result>