If a plane contains the points A and B, it also contains the line AB.
Example Solution: Planes GIJ and GIL
Practice makes perfect
We are given a diagram representing a molecule of phosphorus pentachloride. In this exercise we want to name two planes that contain line s. If two points lie on a plane, and we draw a line that contains both these points, the entire line will be contained in that plane. From the given diagram, we can see that, if our planes of choice contain points G and I, they will also contain the line s.
We can choose point J as the third points needed to define our first plane. We have marked this on the graph. Since this plane contains points G, I and J, we can name it GIJ. For the second plane, we can instead choose L as the third point. This defines the second plane to be GIL, since it contains points G, I, and L.
We have found two planes containing points G and I, plane GIJ, and plane GIL. Line s contains these points, so planes GIJ and GIL contain line s.
