A boat sails 2 km east, then 4 km northeast and then in an unknown direction. Final position of the boat is 5 km east from starting point. Unknown displacement is

S→=S1→+S→2+S→3  5  i^=2i^+  [(4cos450)i^−(4sin450)j^]+S→3     i.e. S→3  =  (3i^−22)i^+22j^=  0 .172 i^+2.828 j^i.e. S3  =  0.1722+2.8282         =  2.8  kmAnd   tanθ=  0.1722.828  =  0.0608Or    θ  =  tan−10.0608Or   θ  =  3026'