Take a scrap piece of the molding and place it vertical at the intersecting point, now draw a line, on the wall, inside and outside of the molding just a smidge past the intersecting points. Now place the piece of molding horizontal at the intersecting point and draw a line inside and outside the molding, on the wall, just a hair past the intersecting point.
Right where the lines on the wall, intersect outside the molding, make a mark on the molding. Now do the same where the inside lines intersect on the inside. Draw a line from dot to dot on the scrap and that is where you want to cut, now do the other piece the same way. Cut the angles and see if they fit, if they do you got it, if not just adjust the cut a little.
I just reread your post, are you trying to go around the corner? If you are here is a link that a friend of mine and a member here wrote about that:
I will have to put the picture on the next post.
