Answer:
Step-by-step explanation:
The scale number can be interpreted as (1cm/3,000,000 km), a conversion factor. Since it is a conversion factor, we can invert it to the form:
(3,000,000 km/1cm)
A measure of 12cm on the map would correspond to:
(12cm)*((3,000,000 km/1cm) = 42,000,000 km
Wow - a long trek, if you need water.
Note that inverting the conversion factor isn't totally necessary, since we could use the original form and divide:
12 cm/(1cm/(3,000,000km)) = 42,000,000 km
But I dislike division, so I always invert a conversion factor if it makes the calculation more convenient, for me.
