Question

A man travels 7 km due north, then goes 3 km due east and then 3 km due south. How far is he from his starting point?

Answer 1

In $\Delta AOB,O$ is right angle.
$\therefore$ Applying Pythogorus theorem,
${\left(AB\right)}^2={\left(OB\right)}^2+{\left(OA\right)}^2$
$=9+16$
${\left(AB\right)}^2=25$
$AB=5$
$\therefore$ He is 5km from starting point.