On a map, use 2 centimeters to represent the actual distance of 9 kilometers, what is the scale of this map
在一幅地图上，用2厘米表示实际距离9千米，这幅地图的比例尺是多少
<gadget id="calculator">1 / 450_000</gadget>
<output>1/450_000 = around 0.000002</output>

<result>1/450_000 = around 0.000002</result>