Ahelicopter rose vertically 300m and then flew west 400m. how far was the helicopter from it starting point?

The helicopter rose vertically, and then flew horizontally, so it's final displacement (distance from where it is now to where it started) is in the shape of a triangle.

The displacement is the hypotenuse of this triangle, with sides 300m and 400m.

We can work out this distance using Pythagorus' theorem, because we know that;



Where  is the hypotenuse, and  and  are the two other sides. So;