On the same map, the straight-line distance between AB and CD is 15 cm, and the straight-line distance between CD is 9 cm. If the actual distance between AB and AB is 1800 km, what is the actual distance between CD and CD?
在同一幅地图上，量得AB两地直线距离为15厘米，CD两地直线距离为9厘米，如果AB两地的实际距离为1800km，那么CD两地的实际距离是多少？
<gadget id="calculator">1_800 * 100_000</gadget>
<output>180_000_000</output>

<gadget id="calculator">15 / 180_000_000</gadget>
<output>1/12_000_000 = around 0</output>

<gadget id="calculator">9 / (1/12_000_000) / 100_000</gadget>
<output>1_080</output>

<result>1_080</result>