The total displacement east is:
15 cos(45) + 15
= 25.607 m
The total displacement north is:
15 sin(45)
= 10.607 m
The magnitude of the total displacement is:
sqrt(25.607^2 + 10.607^2)
= 27.717 m = 27.7 m
Its direction is N x E where:
tan(x) = 25.607 / 10.607
x = 67.5 deg
The return displacement is therefore of the same magnitude
but in the opposite direction.
Displacement 27.7 m, direction S 67.5 deg W