Answer
$3.189\,km$
Work Step by Step
We have three vectors representing the three parts of the path:
$\vec{a} = 3.1\,km\, \hat{i}$
$\vec{b} = -2.4\,km\, \hat{j}$
$\vec{c} = -5.2\,km\, \hat{i}$
We add these up to get the total displacement:
$\vec{t} = -2.1\,km\,\hat{i} - 2.4\,km\,\hat{j}$
The total distance of the displacement is:
$|\vec{t}| = \sqrt{(-2.1\,km)^2+(-2.4\,km)^2} = 3.189\,km$.
