A square park has side length 50m. A boy starts from the south-west corner S, walks north along the western edge to the north-west corner N, then turns right and walks east along the northern edge until he reaches point P, the exact mid-point of the northern edge.
(i) Determine the length NP of the second segment.
(ii) Calculate the total distance travelled from S to P.
(iii) Calculate the magnitude of the displacement from S to P.