On a map with a scale of (1/(7,000,000)), the distance between A and B is 4.2 cm. What is the actual distance in miles between A and B?
在比例尺是(1/(7,000,000))的地图上，甲、乙两城的距离是4.2厘米．甲、乙两城的实际距离是多少千米？
<gadget id="calculator">1 / 7_000_000</gadget>
<output>1/7_000_000 = around 0</output>

<gadget id="calculator">4.2 / (1/7_000_000) / 100_000</gadget>
<output>294</output>

<result>294</result>