Given that, a man goes 35 m due north and then 12 m due west.
Let 'O' be his starting point and OA is the distance travelled along north and AB is the distance travelled along west.
His distance from the starting point is given by length of OB.
OB2=OA2+AB2 [ By Pythagoras theorem]
⇒OB2=OA2+AB2
⇒OB2=352+122
⇒OB2=1225+144
⇒OB2=1369
⇒OB=√1369
⇒OB=37 m
Therefore, he is at a distance of 37 m from the starting point.