Question

the segment in this diagram that divides (overline{ab}) into two congruent parts is called a(n):
angle bisector.
perpendicular bisector.
parallel line

Explanation:

An angle bisector divides an angle into two equal parts. A parallel line is a line that runs alongside another line without intersecting. A perpendicular bisector divides a segment into two congruent parts and is perpendicular to it. In the diagram, the segment divides \(\overline{AB}\) into two congruent parts and is perpendicular, so it fits the definition of a perpendicular bisector.

Answer:

perpendicular bisector.