Given that Phil traveled with his family by car. They started their trip from Lexington to Louisville, driving directly west for 60 miles.
So AB=60
They then turned North, driving to Indianapolis which is 100 miles from Lexington.
So AC=100
Then, they turned to the West again, and drove to Decatur which which is 170 straight miles from Louisville.
so BD=170
Now we have to find about how many miles did they cover in total driving from Lexington to Decatur.
That means we have to find length of (AB+BC+CD)
We can use Pythogorean theorem to find the values of BC and CD.
[tex]BC=\sqrt{AC^2-AB^2}=\sqrt{100^2-60^2}=\sqrt{10000-3600}=\sqrt{6400}=80[/tex]
[tex]CD=\sqrt{BD^2-BC^2}=\sqrt{170^2-80^2}=\sqrt{28900-6400}=\sqrt{22500}=150[/tex]
then (AB+BC+CD)=60+80+150= 290
Hence final answer is miles.