Hello,

I am using the equation Ax + By + Cz + D = 0 to find the equation of a plane through a couple of points and use the Cramer's rule to solve for A,B,C,D.

But what do the A, B,C, D stand for?

I can't find anything on the internet (Maybe I should look harder but I thought I'd ask ) about how to find the angle this plane makes with the origin. How do we find that?