Question

A person goes 3Km towards East, 4km towards North and then 5Km towards North-East. Findhis displacement from his mean position.

Answer 1

So, to find the displacement join the starting and the ending point.
If the direction of the north-east is exactly 45 degrees anticlockwise from the positive x-axis, then we can find that the displacement is a straight line north east.
By pythagoras theorem,
$\sqrt{3^2+4^2}=5$
Another 5 in the north east will give 5+5 = 10 , direction N-E.