Question

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

Explanation:

A perpendicular bisector is a line segment that intersects another line segment at a right angle (90 degrees) and divides it into two equal (congruent) parts. In the given diagram, the segment intersects \(\overline{AB}\) at a right angle and the marks on \(\overline{AB}\) indicate that it is divided into two congruent parts. An angle bisector divides an angle into two equal parts, which is not relevant here as the focus is on a line segment. A parallel line is a line that never intersects another line, which also does not match the description of dividing \(\overline{AB}\) into two congruent parts.

Answer:

perpendicular bisector.