On a map, the actual length is 105km with a length of 3cm. what is the scale of this map
在一幅地图上，用3cm的长度表示实际长度105km．这幅地图的比例尺是多少
<gadget id="calculator">105 * 100_000</gadget>
<output>10_500_000</output>

<gadget id="calculator">3 / 10_500_000</gadget>
<output>1/3_500_000 = around 0</output>

<result>1/3_500_000 = around 0</result>