Intersection of Two Planes

Date: 9/3/95 at 13:17:50
From: jeremy
Subject: geometry

What is the intersection of two planes?

Date: 9/4/95 at 11:58:47
From: Doctor Ken
Subject: Re: geometry

Hello!

When two planes intersect, they can do one of two things:

a) if they're parallel and there are any points in the intersection at all, 
then the intersection has to be the whole plane.  

b) if they're parallel, they don't have to intersect at all.

c) if they're not parallel, the intersection will always be a straight line.

Most planes aren't parallel, so they'd intersect in a line.

- Doctor Ken,  The Geometry Forum