Heart: The intersection of bisectors of three angles is also the center of the inscribed circle of a triangle.

Attribute: The distances to three sides are equal.

Eccentricity: the intersection of three perpendicular lines is also the center of the circumscribed circle of the triangle.

Attribute: The distances to the three vertices are equal.

Center of gravity: the intersection of three midlines.

Property: The distance from the bisector of the three median lines to the vertex is twice the distance from the midpoint of the opposite side.

Vertical center: the intersection of straight lines of three heights.

Attribute: This point is divided into two parts of each high line.

Paracenter: the intersection of the bisector of the outer corner of any two angles of a triangle and the bisector of the inner corner of the third angle.

Attribute: The distances to three sides are equal.

6. The outer angle of a triangle (the angle formed by one side of the inner angle of the triangle and the extension line of the other side) is equal to the sum of the inner angles that are not adjacent to it.

(1) The areas of the three triangles formed by connecting the center of gravity with the three vertices are equal;

(2) The distances between the three vertices of epicentre scanning are equal;

(3) Among the four points, the vertical center and the three vertices, any point is the vertical center of the triangle formed by the other three points;

(4) The distances from the medial center and the lateral center to the three sides are equal;

(5) The vertical center is the center of a triangle composed of three vertical feet, or the center of a triangle is the vertical center of the triangle next to it;

(6) The outer center is the vertical center of the midpoint triangle;

(7) The center is also the center of gravity of the midpoint triangle;

(8) The center of a triangle is also the outer center of its vertical triangle.