Angular bisector: 1. The distance from a point on the bisector of an angle to both sides of the angle is equal. 2. The points from the inside of the corner to both sides of the corner are on the bisector of the corner.

Middle vertical line: 1. Perpendicular bisector is vertical, bisect its line segment. 2. The distance from any point on the perpendicular bisector to both ends of the line segment is equal. 3. The perpendicular lines of the three sides of a triangle intersect at a point, which is called the outer center, and the distance from the point to the three vertices is equal (and the distance is the shortest, only this one).