I'm heading off now so I'll leave you with this.

Tbh, I may have confused you by introducing vectors, sorry. :P The point is, we want a function of the position of the vehicles in terms of time, hence we parameterize the position of the vehicles.

If A is travelling east at 60mph then clearly after 1 hour, A has travelled 60 miles east, after 2 hours 120 miles east, 3 hours 180 miles east

after

hours,

miles east and

miles north.

Similarly for B, after

hours, it has travelled

miles north and

miles east.

Now pythagoras but

**keep** your parameter (i.e.

) when you use pythagoras and you're done.