A line of symmetry,, is a line separating a figure into two halves that are mirror images. Line symmetry exists for a figure if for every point P on one side of the line, there is a corresponding point Q where is the perpendicular bisector of. Line of Symmetry
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A line of symmetry, , is a line separating a figure into two halves
that are mirror images.
Line symmetry exists for a figure if for every point P on one side
of the line, there is a corresponding point Q where is the
perpendicular bisector of .
Line of Symmetry
Figures can be reflected through lines of symmetry onto
themselves.
Lines of symmetry determine the amount of rotation required to
carry them onto themselves.
Not all figures are symmetrical.
Regular polygons have sides of equal length and angles of equal
measure. There are n number of lines of symmetry for a number of
sides, n, in a regular polygon.
Example: Squares
Because squares have four equal sides and four equal angles,
squares have four lines of symmetry.
Rotating a square about its center 90
If we rotate a square about its center 90, we find that though the
points have moved, the square is still covering the same
space.
Similarly, we can rotate a square 180, 270, or any other multiple
of 90 with the same result.
Practice # 1
Given a regular pentagon ABCDE, draw the lines of symmetry.
Continue around to each vertex, extending a line from the vertex to
the midpoint of the opposing line segment.
Note that a regular pentagon has five sides, five vertices, and
five lines of reflection.
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