Warm Up
• Translate the following coordinates:
(-3, -2)(-2, 2)(0,4)  (x + 2, y – 4)
On the graph to the right, translate the
Figure (x + 4, y – 3)
Chapter 13.5
• Vocabulary:
• Reflection
• Line of reflection
Chapter 13.5
• Vocabulary:
• Reflection
• Line of reflection
Is this a reflection?
Is this a reflection?
• To mathematically describe a reflection using coordinate notation,
you write it as the following:
(x,y)  (x, -y)
(x,y)  (-x, y)
Draw a triangle with vertices
(-4, 1) (-1,1) (-3,4)
reflection across the y-axis
Draw a triangle with vertices
(-5, 2) (0,1) (-3,5) reflection
across the x-axis
Draw a triangle with vertices
(-8, -3) (-4,-3) (-6,-8)
reflection across the x-axis
Is this a reflection?
• A figure has line symmetry if a line,
called the line of symmetry, divides
the figure into two parts that are
reflections of each other in the line
How many lines of symmetry does this figure
have?
How many lines of symmetry does this figure
have?
How many lines of symmetry does this figure
have?
Homework
• Page 736
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