1. ## Planes

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?

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?
Hello,

I presume that you have done a little bit vector geometry.

You can write the equation:

$P A, B, C ) \cdot \vec{x} +D=0" alt="P A, B, C ) \cdot \vec{x} +D=0" />

The vector (A,B,C) is the normal(?) vector of the plane and stands perpendicular to the plane.

D divided by the absolute value of vector (A,B,C) gives the distance of the origin to the plane.

Greetings

EB