1. The problem statement, all variables and given/known data do you notice a relationship between the plane and directions of the same miller index? what is it? 2. Relevant equations I've done planes and directions (111), , (112), and  3. The attempt at a solution I believe the direction is normal to the plane on first glance, but I can't seem to do the math to prove it. first off, am I right that the direction is perpendicular and second, how would I begin to prove this?