How to draw the symmetry axis on a ruler?

The ruler can be used as the symmetry axis of the picture, and the ruler can be used as the middle vertical line of the corresponding point of the picture.

How to make the symmetry axis of triangle ABC and triangle A'B'C;

As shown in the figure, with the symmetrical points A and A' corresponding to two triangles as the center and the length more than half the length of AA' as the radius, arcs are drawn on both sides of AA' connecting line, and the two arcs intersect at points M and N to form a straight line MN, which is the symmetry axis of two symmetrical triangle.

Several common axisymmetric and centrosymmetric figures;

1. Axisymmetric graphics: line segment, angle, isosceles triangle, equilateral triangle, diamond, rectangle, square, isosceles trapezoid, circle, hyperbola (with two symmetry axes), ellipse (with two symmetry axes), parabola (with one symmetry axis), etc.

2. The number of symmetry axes: an angle has a symmetry axis, that is, the bisector of the angle; The isosceles triangle has an axis of symmetry, which is the median vertical line of the base; An equilateral triangle has three axes of symmetry, that is, the median vertical lines on three sides; A diamond has two symmetry axes, which are straight lines where two diagonals are located, and a rectangle has two symmetry axes, which are straight lines between two groups of opposite sides.

3. Centrally symmetric figures: line segments, parallelograms, diamonds, rectangles, squares, circles, etc.

4. Symmetry center: the symmetry center of the line segment is the midpoint of the line segment; The symmetrical centers of parallelogram, rhombus, rectangle and square are the intersections of diagonal lines; The symmetrical center of a circle is the center of the circle.