1, three methods of graphic transformation:

First translation: explain which direction to translate (up, down, left and right) several times.

Second turn: you need to specify which point to turn, clockwise or counterclockwise, and how many degrees to turn (90 degrees, 180 degrees, 270 degrees).

The third kind of symmetrical figure: it shows which straight line is the symmetrical figure of which figure.

Exercise-symmetry

1. Judgment

Please judge whether each figure is axisymmetric in turn. If you use gestures to indicate the position of the axis of symmetry, if not, please explain why.

Summary: Whether there is an axis of symmetry is the basis for judging the axisymmetric figure. It seems that the axis of symmetry is very important for axisymmetric graphics.

Look for it.

(1) Provide the axis of symmetry: Can you find a point symmetrical with it? How can you be sure?

Summary: There seems to be a reciprocal relationship behind the symmetry phenomenon.

(2) Now that one side of the symmetry axis is a line segment, can we still find a line segment symmetrical with it?

Summary: As long as the symmetrical points of the two endpoints are found and connected, the line segment must be symmetrical with the original line segment.