(a) < ZXY = 225^\circ - 135^\circ = 90^\circ. \(\therefore /ZY/ = 80^{2} + 60^{2}\) = \(6400 + 3600 = 10000\) \(/ZY/ = \sqrt{10000}\) = 100 km. (b) From \(\Delta\) XYZ, \(\tan \theta = \frac{opp}{adj}\) \(\tan \theta = \frac{80}{60} = 1.333\) \(\theta = \tan^{-1} (1.333)\) \(\theta = 53.13^\circ\) Bearing of Z from Y = \(360^\circ - (45^\circ + 53.13^\circ)\) = \(360^\circ - 98.13^\circ\) = \(261.87^\circ \approxeq 262^\circ\) (3 significant figures)