A figure with only one axis of symmetry is called a mirror symmetrical figure or an axisymmetric figure. Axisymmetry is a very important concept in mathematics and geometry, which describes the mirror symmetry of a figure or object relative to an axis.
In order to understand mirror symmetry, we first need to understand the following basic concepts:
Symmetry axis: Symmetry axis is an imaginary line, which can be divided into two identical parts through the center or a certain point of the figure. Every point of a graph has a corresponding point about the axis of symmetry, and the distance between the two corresponding points is equal to the vertical distance of the axis of symmetry.
Axisymmetric figure: If a figure is axisymmetric with respect to a line, it is called an axisymmetric figure. This means that each point of the graph has a corresponding point on the other side of the symmetry axis, and the distance between them is equal to the symmetry axis, so the whole graph can be mirrored and reversed through the symmetry axis.
Non-axisymmetric graphics: Compared with axisymmetric graphics, non-axisymmetric graphics are not axisymmetric. This means that it can't get itself through mirror image flip, or at least it needs more than two symmetry axes to achieve it.
Now let's look at some examples of graphs with only one axis of symmetry:
Circle: A circle is one of the simplest axisymmetric figures. Its axis of symmetry divides the circle into two identical semicircles by the diameter of the center of the circle. Any point on a circle has a corresponding point on the other side of the axis of symmetry, and the distance between them is equal.
Square: A square is also an axisymmetric figure. The midpoint along its two diagonals can be divided into two equal triangles, which can be mirrored by the symmetry axis.
Rectangle: a rectangle is also an axisymmetric figure with an axis of symmetry. It can be divided into two equal halves through the center of the rectangle, and the two halves can be mirror images of the axis of symmetry.
Letter "H": The letter "H" is also an axisymmetric figure. Its axis of symmetry is perpendicular to the horizontal bar, and the letter "H" can be divided into two equal parts.
Letter "I": Similar to the letter "H", the letter "I" is also axisymmetric. Its axis of symmetry lies in the middle of the letter "I" and can be divided into two equal parts.