vertical line is the vertical bisector line.

Passing through the midpoint of a line segment and perpendicular to the straight line is called the perpendicular bisector

vertical bisector line, referred to as "middle vertical line", is a very important part of junior high school geometry. Use a straight line to divide a line segment into two equal lines from the middle, and perpendicular to the line segment, this line straight line is called the vertical bisector of this line segment. It is usually made by drawing with a compass and a ruler.

Let the coordinates of the two end points of the line segment be (x1,y1), (x2,y2)

then the vertical bisector Equation can be obtained by equalizing the distance between the first point of the line and the two endpoints:

(x-x1)^2+(y-y1)^2=(x-x2)^2+(y-y2)^2

2(x1-x2)x+2(y1-y2)y=x1^2+y1^2-x2^2-y2^2