Final answer:
To find the actual distance between two cities on a map with a scale of 1 inch:15 miles, multiply the distance on the map in inches (4) by the scale factor (15), which equals 60 miles. Therefore, the cities are 60 miles apart.
Step-by-step explanation:
If a map has a scale of 1 inch:15 miles and two cities are 4 inches apart on the map, to find out how far they are actually apart, you need to set up a proportion. Since each inch on the map represents 15 actual miles, you can multiply the number of inches by the scale factor. Here's how you calculate it:
Distance on map (in inches) x Scale factor (miles per inch) = Actual distance (in miles)
4 inches x 15 miles/inch = 60 miles
So, the two cities are actually 60 miles apart.