Question

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Explanation:

1. Segment AB is perpendicular to the base and splits it into two equal parts, meeting the definition of a perpendicular bisector.
2. Segment AB connects midpoints of two sides, so it is none of the listed triangle segments.
3. Segment AB splits the vertex angle into two equal parts, so it is an angle bisector.
4. Segment AB forms a right angle with the side it intersects, so it is an altitude.
5. Segment AB connects a vertex to the midpoint of the opposite side, so it is a median.
6. Segment AB connects a vertex to the midpoint of the opposite side, so it is a median.

Answer:

1. perpendicular bisector
2. none of these
3. angle bisector
4. altitude
5. median
6. median