Answer:
B.) 
Step-by-step explanation:
use the slope rule

Fill in values

Simplify

Simplify further

Done.
Hi , the answer is 600 , because 3920 miles divided by 420 minutes[7hours] equals to 9.33 and 9.33 times 60 minutes[1 hour] equals to 559.8 , which is an approximate of 600.
Answer:
what? Is this like a challenge or something?
The missing length is 51.5, I hope this helps :)