GPA Math 90: 7.5 - Reflections and Line Symmetry Notes
What is symmetry?
An object or image has symmetry if it is balanced and can fit onto itself either by __________
_________________________________________________________.
How many lines of symmetry does this pentagon have?
_________ line of symmetry. AG divides it into _______
congruent pairs.
Also, each point on one side of the line of symmetry has a _________________
on the other side of the line. These two points are the ____________________,
or __________________________________ from the line of symmetry.
A line of symmetry is also called a ____________________. Think of the line
as a mirror.
The original image and the reflection make one larger shape
but are also mirror images of each other. Thus a line of
__________________ is also a _____________________.
Example 1 - Identifying Lines of Symmetry in Tessellations
A tessellation is a pattern or arrangement that covers an area or plane without overlapping or
leaving gaps. It can also be called a tiling pattern.
How many lines of symmetry?
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GPA Math 90: 7.5 - Reflections and Line Symmetry Notes
How many lines of symmetry?
Example 2 - Identifying Shapes Related by a Line of Symmetry
Identify the triangles that are related to the shaded triangle by a line
of reflection.
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GPA Math 90: 7.5 - Reflections and Line Symmetry Notes
Example 3 - Completing a Shape Given it's Line of Symmetry
Quadrilateral ABCD is part of a larger shape. We will draw the shape after each reflection
stated. We will also write the coordinates of all of the points of the larger shape formed by
ABCD and its image.
a) A reflection in the horizontal line through 12 on the y-axis.
Each image point is the same distance from this line as the corresponding original point
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GPA Math 90: 7.5 - Reflections and Line Symmetry Notes
b) a reflection in an oblique line through (11,14) and (3,6).
Assignment:
Assignment Due:
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