The distance between Hangzhou and Ningbo is 180 kilometers. How many centimeters should be drawn on a map with a scale of 1:4,000,000?
杭州和宁波相距180千米，画在一幅比例尺为1：4000000的地图上，应该画多少厘米．
<gadget id="calculator">1 / 4_000_000</gadget>
<output>1/4_000_000 = around 0</output>

<gadget id="calculator">180 * 100_000 * (1/4_000_000)</gadget>
<output>9/2 = around 4.5</output>

<result>9/2 = around 4.5</result>