Question

Brandon uses the following steps to construct a perpendicular line through a point C on a line segment. He first draws two arcs from point C intersecting the line segment in points A and B. The next four steps are listed below:

Answer 1

Step 1: Using the same compass width draw two more arcs from point C, one above and the other below the line.
Step 2: Without changing the compass width, draw two arcs from point B above and below the line segment.
Step 3: Label the point of intersection of the arcs above the line segment as M and below the line as N.
Step 4: Using a straightedge, join point M and point N.

Answer 2

Part A: Which is the first incorrect step?
Part B: Using complete sentences, explain your answer for Part A.
Part C: Explain why a compass works for the construction done by Brando

Answer 3

I already know step 1 is the incorrect step, I'm having trouble explaining it.