Nevermind, I confused the direction of a vector with the cosine distance.
I can see they are related.

The direction it’s related to the usage of SoHCah---->[Toa].
Where Tan(opposite/adjacent) = tan(θ), and the usage of it’s inverse arctan(opposite/adjacent)=θ.

But then I notice that the cosine distance was being use in a not right triangle.
As SoHCaHToa it’s related to the cosine distance, then I thought that cosine distance could only be applied (just as SoHCaHToa) to right triangles.

But I can see now, that it can be applied to any kind of triangle.