A boat crosses a river (need help)

I have a hard time understanding this thing, I though I had to use pythagore but I don't know anymore :|

a) A boat crosses a river at a vectorial speed of 4.8m/s, going north.
The river has a current of 1.4m/s going west.
What's the apparent vectorial speed of the boat from the point of view of someone on the coast ?

b) from the observer point of view, whats the orientation of the boat ?

c) how long will the boat take to cross the river?

d) what's the deviation of the boat when it gets on the other shore ?

This helps for question a)
**broken link removed**

b) If the vectorial speed of the boat is towards north, then the orientation is to north.

c) How wide is the river? The boat is approaching the other side at 4.8 m/s.

d) How wide is the river? The boat is "deviating" at 1.4 m/s.

The insight needed to solve the problem is that the two velocity vectors add vectorially. Put a two-dimensional Cartesian coordinate system at rest on the bank of the river and draw a picture. Hopefully, the answer to a) is then obvious. The other answers just need simple kinematic equations.

Added: oops, didn't see misterT's response!

thank you so much, I see it clear now, the angle approach was the one I needed to focus on !