Definition: A straight line passing through the midpoint of a line segment and perpendicular to this line segment is called the median line of this line segment, also called the median line of this line segment.

The theorem of the perpendicular line in the line segment: the point on the perpendicular line in the line segment is equal to the distance between the two ends of the line segment.

What is the center?

Definition: The center of the circumscribed circle of a regular polygon is called the center of a regular polygon.

What is the center of gravity?

The center of gravity of a triangle is the intersection of three sides. The center of gravity of the line segment is the midpoint of the line segment. The center of gravity of a parallelogram is the intersection of its two diagonals. The center of gravity of a circle is the center of the circle, and the center of gravity of a ball is the center of the ball.

Angular bisector?

A ray bisecting an angle is called the bisector of this angle.

Perpendicular bisector?

Is the center line of the line segment.

High line?

It is the height of a triangle: the line segment passing through a vertex of the triangle and perpendicular to the opposite side or the extension line of the opposite side is called the high line of the triangle.