Definition of symmetrical figure (axisymmetric figure): In a plane, if a figure is folded along a straight line, the parts on both sides of the straight line can completely overlap. Such a graph is called an axisymmetric graph. Features: In an axisymmetric figure, the distance between the corresponding points on both sides of the axis of symmetry is equal. In an axisymmetric figure, it is folded in half along the axis of symmetry, and the left and right sides are completely coincident.

Axisymmetric graphics, in mathematical terms, are defined as graphics folded along a straight line in a plane, and the parts on both sides of the straight line can completely overlap. A straight line is called the axis of symmetry, and the axis of symmetry is represented by a dotted line. At this time, we also say that this figure is symmetrical about this line. Such as circle, square, isosceles triangle, equilateral triangle, isosceles trapezoid, etc.

Determination of axisymmetric figure

A straight line that passes through the midpoint of a line segment and is perpendicular to the line segment is called the midline of the line segment. In this way, the following properties are obtained: if two graphs are symmetrical about a straight line, then the symmetry axis is the middle perpendicular of the line segment connected by any pair of corresponding points.

Similarly, the symmetry axis of an axisymmetric figure is the median vertical line of a line segment connected by any pair of corresponding points. The point on the vertical line in a line segment is equal to the distance between the two endpoints of the line segment. Symmetry axis is the set of points with equal distance to both ends of a line segment. Only axisymmetric figures are: angle, pentagram, isosceles triangle, equilateral triangle, isosceles trapezoid and so on.

Refer to the above content: Baidu Encyclopedia-Axisymmetric Graphics