The Bonneville Salt Flats, located in Utah near the border with Nevada, not far from Interstate I80, cover an area of over 30,000 acres. A race car driver on the Flats first heads north for $4.47 \mathrm{~km},$ then makes a sharp turn and heads southwest for $2.49 \mathrm{~km},$ then makes another turn and heads east for $3.59 \mathrm{~km}$. How far is she from where she started?