On a map with a scale of (1/4500000), the distance between Shangdao County and Hengyang is 4 cm. What is the actual distance between Dao County and Hengyang in kilometers?
在比例尺为(1/4500000)的地图上量出上道县到衡阳的距离是4厘米，道县到衡阳的实际距离是多少千米．
<gadget id="calculator">1 / 4_500_000</gadget>
<output>1/4_500_000 = around 0</output>

<gadget id="calculator">4 / (1/4_500_000) / 100_000</gadget>
<output>180</output>

<result>180</result>