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.
![d = \sqrt{(5-1) ^(2)+ (5-2) ^(2) }](https://img.qammunity.org/2019/formulas/mathematics/high-school/eldz7c5xkd4dx0fp9mgnub5milhwfcvx7p.png)
![d= \sqrt{(4) ^(2)+ (3) ^(2) }](https://img.qammunity.org/2019/formulas/mathematics/high-school/h6ps6yfo0prsw5sr18jdyqzkppe4wn2xzb.png)
![d = √(16 + 9)](https://img.qammunity.org/2019/formulas/mathematics/high-school/zuli8aqr5707aa5vjoymjo9ozzwu9mbf8s.png)
![d = √(25) = 5](https://img.qammunity.org/2019/formulas/mathematics/high-school/3ip4ji3cnfvz9wp0oun3wroipkdjjncxkr.png)
Given that each unit represents one mile, then therefore the ship has sailed 5 miles, which is choice A.