His movements 1km due east and then 1 km due north make a Right-Angled Triangle. Using Pythagoras' theorem; The Resultant becomes the Hypotenuse [h] Hyp\(^2\) = Adj\(^2\) + \Opp(^2\) Hyp\(^2\) = 1\(^2\) + 1\(^2\) Hyp\(^2\) = 2 → Hyp = \sqrt2 : Resultant = \sqrt2 DIRECTION TAN Ø = \(\frac{OPP}{ADJ}\) TAN Ø = \(\frac{1}{1}\) Ø = TAN\(^{-1}\) [1] Ø= 45^\circ Displacement is \sqrt2km N 45^\circE