How to rotate half of a plane around the split edge after cutting it in half using loop cut I have split a plane in half by using the Loop Cut tool and now I have two faces which both share an edge. When I select just one of the faces and press R+Y to rotate it, it rotates around an axis which goes through its center of area. This causes the other face to follow the shared edge as the first one rotates and sort of stretch.

I am not sure how to make my selection so that Blender knows to rotate the face around the shared edge. What I am after is rotation one of the faces around an edge shared with the other as if you were opening and closing a book, its spine being the shared edge.

I read some answers, but most that I could find deal with rotating an object around on of its edges. I also couldn't get some of them to work. This is different from what I want to achieve, I am trying to rotate one face within a mesh without affecting the rotation, location or shape of the other faces of the mesh.

I am using Blender 2.80 beta.
Select the edge, set the 3d cursor to it (Shift+S, 4); Set the cursor as the pivot point for rotation (Dot); then select your face, and create a new custom transform orientation, it will give you the correct gizmo axes for rotation (if your edge matches any of the world axes you can skip this step); rotate as you wish. :-)
You can also use the "Active element" as your pivot point. In this case you have to select all the edges of your plane to rotate, and the "hinge" edge should be selected last (to become that active element).
And for the simple plane you can also use "Normal" as your transform orientation (it works great in this case, and you have not to deal with creating custom transform orientations).