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?
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Equivalent Transformations and Symmetry

Unit 4: Transformations
Lesson 4 of 6

Objective: SWBAT find rotations and reflections that map a figure onto itself, and find single transformations that are equivalent to a composition of transformations.

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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2 teachers like this lesson
Math, Geometry, Symmetry, Constructions and Transformations, dilation, reflection, transformation, horizontal, vertical, translations, rotations, point symmetry
  90 minutes
image symmetry
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