Name: ______________________ Date: _______________

Math 9 Chapter 7 Similarity and Transformations

Lesson 7.5 Reflections and Line Symmetry Line Symmetry - _________________________________________________________

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If we fold a shape along its line of symmetry, the parts match exactly Example 1: How many lines of symmetry does this pentagon have?

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.

Example 2: 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?

Example 3: Identify the triangles that are related to the yellow triangle by a line of reflection

Example 4: Quadrilateral ABCD is part of a larger shape.

Complete the shape if ABCD is a:

a) Reflection in the horizontal line through 2 on the y-axis.

b) Reflection in the oblique (diagonal) line through (0, 0) and (6, 6).

c) Reflection in the vertical line through 5 on the x-axis.

Label each shape with the coordinates of its vertices

a) b) c)

Example 5: Copy each polygon onto grid paper. It is one-half of a shape. Use the given line of

symmetry to complete the shape by drawing its other half. Label the shape with

the coordinates of its vertices.

a) Horizontal line through 1 on the y-axis. b) Vertical line through 5 on the x-axis.

Assignment: Pages 357 – 359, #1 -6, 8 – 10, AFQ #7, Reflect