Given a man goes 15 m due west and then 8 m due north
Let O be the starting point and P be the final point.
Then OP becomes the hypotenuse in the triangle.
So by using the Pythagoras theorem, we can find the distance OP.
OP2 = 152 + 82
OP2 = 225 + 64
OP2 = 289
OP = 17
Hence, the required distance is 17 m.