Hello!
To find how far the ship has sailed, we need to use the distance formula. The distance formula is:
.
Before using the formula, we need to assign the given points to
and
. The point (1, 2) can be assigned to
and (5, 5) can be assigned to
.
With the assigned ordered pairs, we can substitute it into the formula.




Given that each unit represents one mile, then therefore the ship has sailed 5 miles, which is choice A.