Properties of angular bisector: the angular bisector can get two equal angles; The distance from the point on the bisector of the angle to both sides of the angle is equal; The three bisectors of a triangle intersect at a point, which is called the triangle center. The distance from the center of the triangle to the three sides of the triangle is equal; The bisector of the angle of a triangle. The two line segments formed by the opposite sides of the bisector of the angle are proportional to the two adjacent sides of the angle.

The distance from the point on the bisector of the angle to both sides of the angle is equal, which is the distance from the pointing to the straight line. Otherwise, the line segments can't be equal, the distance from the point on the bisector of the outer corner to the extension line opposite to the two sides of the corner is equal, and the distance from the point on the bisector of the corner is equal.

The property theorem of the bisector of the triangle inner angle is that the bisector of the triangle is divided into two line segments, so these two line segments are proportional to both sides of the angle. The judgment theorem of the bisector of the triangle inner angle is ⊿ABC. If point D presses the BC side of the score between AB side and AC side, then the segment AD is the bisector of ∠BAC.

The bisector of a triangle intersects the opposite side of the angle. The line segment connecting the vertex of the angle and the intersection with the opposite side is called the bisector of the triangle, also called the bisector of the inner angle of the triangle. By definition, the bisector of a triangle is a line segment. Because a triangle has three internal angles, it has three bisectors, and the intersection of the bisectors must be inside the triangle.