2. Then take A as the center, draw an arc whose length is more than half of the line segment AB.

3. Then you need to draw an arc with B as the center and equal length as the radius. The arc before intersection is at two points of MN.

4. Finally, connect MN, which is the middle vertical line of line segment AB.

Extended data

A straight line passing through the midpoint of a line segment and perpendicular to this line segment is called the median line of this line segment, also known as the "median line". The median vertical line can be regarded as a collection of points with the same distance to the two endpoints of a line segment, and the median vertical line is the symmetry axis of the line segment.

It is a very important part of junior high school geometry. The median vertical line divides a line segment into two equal line segments from the middle, and they are perpendicular to the divided line segment (at an angle of 90).