Question

a student lists steps to construct the perpendicular bisector of a segment sd.
step description
1 place the compass at s.
2 set the compass width to slightly less than half the length of sd.
3 draw arcs above and below the segment.
4 place the compass at d.
5 without changing the compass width, draw arcs above and below the segment.
6 connect the points of intersection of the arcs by a line segment.
in which step does the student make the first error?
step 1
step 2
step 4
step 5

Explanation:

Step1: Recall construction principle

To construct the perpendicular - bisector of a line segment, the compass width should be set to more than half the length of the segment.

Step2: Analyze each step

In step 2, setting the compass width to slightly less than half the length of $SD$ is incorrect. It won't ensure that the arcs from both ends of the segment intersect above and below the segment.

Answer:

Step 2