Answer:the coastline is 20000 miles.
The land boundaries are 12000 miles.
Step-by-step explanation:
The length of the entire border of the Unites States is approximately 32,000 miles.
5/8 of the entire length is the coastline. It means that the length of the coastline of the U.S would be
5/8 × 32000 = 20000 miles.
Therefore, the length of the boundaries of the US would be
32000 - 20000 = 12000 miles.
