On a map with a scale of 1:30000000, the distance between A and B is 4 cm. What is the actual distance between A and B in kilometers?
在比例尺是1：30000000的地图上，量得甲、乙两地相距4厘米，甲、乙两地的实际距离是多少千米？
<gadget id="calculator">1 / 30_000_000</gadget>
<output>1/30_000_000 = around 0</output>

<gadget id="calculator">4 / (1/30_000_000) / 100_000</gadget>
<output>1_200</output>

<result>1_200</result>