Is there a line that is already perpendicular to BF?
Yes you can Explanation: See solution.
Practice makes perfect
The Perpendicular Postulate states that if there is a line and point not on the line, then there is exactly one line through the given point perpendicular to the given line. From the diagram, we see that DM is a line that passes through point M and is perpendicular to BF.
That must mean that AC cannot be perpendicular to BF as there can be only one such line passing through point M.
