3 cm on the map means the actual distance is 3 kilometers. A section of road is 25 kilometers long, how many centimeters should be drawn on this map.
图上3厘米表示实际距离3千米．一段公路长25千米，画在这幅地图要画多少厘米．
<gadget id="calculator">3 * 100_000</gadget>
<output>300_000</output>

<gadget id="calculator">3 / 300_000</gadget>
<output>1/100_000 = around 0.00001</output>

<gadget id="calculator">25 * 100_000 * (1/100_000)</gadget>
<output>25</output>

<result>25</result>