On a map with a scale of 1:200000, the distance between the two places is 4 cm. What is the actual distance in kilometers.
在比例尺是1：200000的地图上，量得两地间的距离是4厘米．实际距离是多少千米．
<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>