Suppose a mirror was to be placed flat on a wall that is perpendicular to the floor. What is the shortest mirror a 6 foot tall person could use so as to be able to see an image in the mirror from the top of the head to the toes? Assume the person is standing 5 feet from the mirror.
What principle is involved?
Will the needed mirror be the same height if you were standing 10 feet away? Why?