Answer
$4.47$ miles (approximately)
Work Step by Step
Apply Pythagorean theorem.
$c^2=a^2+b^2$
Plug $a=4$ miles and $b= 2$ miles.
We have $c^2=4^2+2^2=16+4$
or, $c^2=20$
or, $c=\sqrt {20}$
or, $c=2\sqrt 5$
or $c=4.47$ miles (approximately)
