An aeroplane flies due north from Ikeja airport for 400km. It flies on a bearing of 060° for a further distance of 200km before overflying a road junction find the distance of the aeroplane from Ikeja airport when it was directly above the road junction.

Answer 1

Draw a diagram, and study the law of cosines.
d^2 = 400^2 + 200^2 - 2(400)(200) cos120°