The angular bisector has two properties. The first point is that the angle is divided into a pair of equal angles by the bisector, and the second point is that the points on the bisector are equidistant from both sides of the angle.

The properties of the bisector in a triangle are as follows: the three bisectors of a triangle intersect at a point, and the distances to each side are equal, which is called the center; Divide the bisector of the inner angle of a triangle into opposite sides, and the two line segments obtained are proportional to the two sides of this angle.

Draw a ray from the vertex of an angle that is divided into two identical angles. This ray is called the bisector of an angle, and the bisector of an angle is the locus of points with the same distance on both sides of the angle. The intersection of bisectors of three angles of a triangle is called the center of the triangle.

The distance from the center of a triangle to the three sides is equal, which is the center of the inscribed circle of the triangle.