## Reflection: Vertical Alignment Equivalent Transformations and Symmetry - Section 4: Symmetry: Having the Students Unpack the Standard

In the Grade 4 Common Core Math Standards, there exists:

• CCSS.Math.Content.4.G.A.3 Recognize a line of symmetry for a two-dimensional figure as a line across the figure such that the figure can be folded along the line into matching parts. Identify line-symmetric figures and draw lines of symmetry.

This might lead one to wonder about my inclusion of the Alphabet Symmetry task in a high school geometry lesson.  I think it is helpful for students to apply new ideas in familiar situations. For example, the level of understanding has been taken up a notch here, as the students also look for new concepts like point symmetry.

Additionally, my students had very productive discussions with an interesting, but meaningful perspective: How does the choice of font impact the symmetry of the alphabet?

• Could "K" be drawn so that it does have line symmetry?
• Does this O have only two lines of symmetry?
• Could O have been drawn so that it has an infinite number of lines of symmetry?
• How could Q be drawn so that it has line symmetry?

I found this to be a worthwhile exercise in which students generated a number of interesting conjectures and demonstrated their facility with mathematical practices (MP2, MP3).

Vertical Alignment: Is This Exercise in Alphabet Symmetry Appropriate for High School?

# Equivalent Transformations and Symmetry

Unit 4: Transformations
Lesson 4 of 6

## Big Idea: Symmetry in terms of reflections and rotations. Students unpack the standard and solidify their knowledge of compositions of transformations.

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Standards:
Subject(s):
Math, Geometry, Symmetry, Constructions and Transformations, dilation, reflection, transformation, horizontal, vertical, translations, rotations, point symmetry
90 minutes

### Beth Menzie

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