Perpendicular Bisectors & Midpoints

Students carefully examine the figure shown and verify if the midpoint of a line segment can be related to perpendicular bisectors.
[1] How can you verify that point C is a midpoint of line segment AB? [2] Is line segment DC perpendicular to line segment AB? How did you know? [3] How are slopes of perpendicular lines related? [4] Is line segment DC a perpendicular bisector? Explain your answer.