Let the directions are defined by vectors as following
East = + x direction
West = - x direction
North = + y direction
South = - y direction
upwards = + z direction
downwards = - z direction
So here we are given that it moves
1). 10 m East
2). 9 m South
3). 3 m North
4). 2 m down
So we can write it as
Now total displacement will be given as
now the magnitude of the displacement will be
so the magnitude of displacement will be 11.8 m