Download Unit 13 symmetry.notebook

Unit 13 symmetry.notebook
April 14, 2016
Warmup: Rotate point R 90o, 180o, and 270o counterclockwise about the origin, and find the coordinates of the images.
(3, 4)
R(­4, 3)
R(4, ­3)
R(­3, ­4)
Symmetry
Rotational symmetry: a rotation maps the figure onto itself.
If an isometry maps a figure onto itself, then the figure has symmetry.
Reflectional (or line) symmetry: a reflection maps the figure onto itself.
sides
If we rotate the hexagon 60 degrees, the image is exactly the same as the original, so the hexagon has rotational symmetry, and the angle of rotation is 60 degrees.
Point symmetry: a 180 degree rotation maps the figure onto itself.
If we reflect this regular pentagon around the dotted red line, the image is exactly the same as the original, so the dotted red line is a line of symmetry.
How many lines of symmetry does this pentagon have?
5
If we rotate the figure 180 degrees, the image is exactly the same as the original, so the figure has point symmetry.
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Unit 13 symmetry.notebook
April 14, 2016
RCLOPQTWWYMWTBF:
1.) Draw and write Translations
2.) Draw and write Reflections
3.) Draw and write Rotations
4.) Identify various types of symmetry
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