The so-called "four hearts" of a triangle refers to the center of gravity, center of gravity, outer heart and inner heart of the triangle. When a triangle is a regular triangle, the four centers coincide as a point, which is collectively called the center of the triangle.

First, the outer center of the triangle

Definition: The intersection of three perpendicular lines of a triangle is called the outer center.

Second, the center of the triangle.

Definition: The intersection of bisectors of three angles of a triangle is called the center of the triangle, that is, the center of the inscribed circle. Heart is generally represented by letters, and it has the following properties:

Third, the center of the triangle.

Definition: The intersection of three heights of a triangle is called the center of gravity. The center of gravity is generally indicated by letters.

Fourth, the "center of gravity" of the triangle:

Definition: The intersection of the three midlines of a triangle is called the center of gravity. The center of gravity is generally indicated by letters.