First let's add all the inches together.
3.2 + 0.9 + 2.2 + 0.5 = 6.8
Now divide
11.56/6.8 = 1.7
Each inch represents 1.7 miles :)
Hopefully this helps! If you have any more questions or don't understand, feel free to DM me, and I'll get back to you ASAP! :)