On a map with a scale of 1:300000, the distance between A and B is 12 cm. If the scale is 1:500000, how many centimeters should the distance between A and B be drawn?
在比例尺是1：300000的地图上，量得甲、乙两地的距离是12厘米，如果改用1：500000的比例尺，甲、乙两地的距离应画多少厘米．
<gadget id="calculator">1 / 300_000</gadget>
<output>1/300_000 = around 0.000003</output>

<gadget id="calculator">12 / (1/300_000)</gadget>
<output>3_600_000</output>

<gadget id="calculator">1 / 500_000</gadget>
<output>1/500_000 = around 0.000002</output>

<gadget id="calculator">3_600_000 * (1/500_000)</gadget>
<output>36/5 = around 7.2</output>

<result>36/5 = around 7.2</result>