Final answer:
Using a derived map scale from the known distance between two peaks, the map distance between river A and river B is calculated to be 1.23 inches based on the scale proportion of 12.3 inches representing 1,000 miles.
Step-by-step explanation:
The question relates to the concept of map scale which is often addressed in mathematics, specifically in topics involving ratios and proportions. To find the distance on the map from river A to river B, we need to use the map's scale that we derive from the given information.
Firstly, we determine the scale based on the distance between mountain peak A and B. The map shows 12.3 inches for 1,000 miles. Then, we use a proportion to find the map distance for 100 miles, which is the actual distance between river A and B.
The scale can be expressed as:
1 inch / (1,000 miles / 12.3 inches) = X inches / 100 miles
Now we solve for X:
X = (100 miles * 12.3 inches) / 1,000 miles = 1.23 inches
So, the distance on the map between river A to river B is 1.23 inches.