On a map with a scale of 1:200000, the distance between A and B is 4 cm. What is the actual distance between A and B in kilometers?
在比例尺为1：200000的地图上量得甲、乙两地的距离为4厘米，甲、乙两地的实际距离为多少千米．
<gadget id="calculator">1 / 200_000</gadget>
<output>1/200_000 = around 0.000005</output>

<gadget id="calculator">4 / (1/200_000) / 100_000</gadget>
<output>8</output>

<result>8</result>