I am trying to make a turbine with cuts in the sides. I did this with the knife tool and copied the vertices made with the knife tool to the areas marked on the picture. At the place where I used the knife tool I could remove the faces and create the cut shown on the picture. However, the vertices I copied are just floating in space and are not connected to the mesh. This is why the edges (see 'to here') look like they are attached but they are not. Because of this, I cannot remove the faces as I did with the original cut.
The selected area is only 1 face, I want to select the triangle in the selected area
How do I fix this? Can I attach them to the mesh? Or is there another workflow that works better?