The railway line from Beijing to Jinan is about 4,900km long. On a map with a scale of 1:7,000,000, how many centimeters is the length of the railway line?
北京到济南的铁路线大约长4900km，在比例尺是1：7000000的地图上，铁路线的长是多少厘米？
<gadget id="calculator">1 / 7_000_000</gadget>
<output>1/7_000_000 = around 0</output>

<gadget id="calculator">4_900 * 100_000 * (1/7_000_000)</gadget>
<output>70</output>

<result>70</result>