Transformations and Congruence *
G-CO.1, G-CO.2, G-CO.3, G-CO.4, G-CO.5, G-CO.12, G-CO.13, G-GPE.4, G-GPE.5, G.GPE.7, F-BF.3: Explore congruence of triangles, including quadrilaterals built from triangles, through geometric constructions. Investigate transformations in the plane. Use geometry software to study transformations, developing definitions of rotations, reflections, and translations in terms of angles, circles, perpendicular lines, and parallel lines. Express translations algebraically (CDE 2023, 58).
California Department of Education. 2023. Mathematics Framework Chapter 8. Sacramento, CA: California Department of Education.
Big Idea Success Criteria
The categories and their related standards below unpack the success criteria of this big idea.
Secondary Standards
- Make geometric constructions. [Formalize and explain processes.] (G-CO.12, G-CO.13) (CDE 2013, 134)
- G-CO.12. Make formal geometric constructions with a variety of tools and methods (compass and straightedge, string, reflective devices, paper folding, dynamic geometric software, etc.). Copying a segment; copying an angle; bisecting a segment; bisecting an angle; constructing perpendicular lines, including the perpendicular bisector of a line segment; and constructing a line parallel to a given line through a point not on the line (CDE 2013, 134).
- G-CO.13. Construct an equilateral triangle, a square, and a regular hexagon inscribed in a circle (CDE 2013, 134).
Primary Standards
- Experiment with transformations in the plane. (G-CO.1, G-CO.2, G-CO.3, G-CO.4, G-CO.5) (CDE 2013, 72)
- G-CO.1. Know precise definitions of angle, circle, perpendicular line, parallel line, and line segment, based on the undefined notions of point, line, distance along a line, and distance around a circular arc (CDE 2013, 72).
- G-CO.2. Represent transformations in the plane using, e.g., transparencies and geometry software; describe transformations as functions that take points in the plane as inputs and give other points as outputs. Compare transformations that preserve distance and angle to those that do not (e.g., translation versus horizontal stretch) (CDE 2013, 72).
- G-CO.3. Given a rectangle, parallelogram, trapezoid, or regular polygon, describe the rotations and reflections that carry it onto itself (CDE 2013, 72).
- G-CO.4. Develop definitions of rotations, reflections, and translations in terms of angles, circles, perpendicular lines, parallel lines, and line segments (CDE 2013, 72).
- G-CO.5. Given a geometric figure and a rotation, reflection, or translation, draw the transformed figure using, e.g., graph paper, tracing paper, or geometry software. Specify a sequence of transformations that will carry a given figure onto another (CDE 2013, 72).
- Use coordinates to prove simple geometric theorems algebraically. [Include distance formula; relate to Pythagorean Theorem.] (G-GPE.4, G-GPE.5, G.GPE.7) (CDE 2013, 74)
- G-CO.4. Develop definitions of rotations, reflections, and translations in terms of angles, circles, perpendicular lines, parallel lines, and line segments (CDE 2013, 72).
- G-CO.5. Given a geometric figure and a rotation, reflection, or translation, draw the transformed figure using, e.g., graph paper, tracing paper, or geometry software. Specify a sequence of transformations that will carry a given figure onto another (CDE 2013, 72).
- G-GPE.7. Use the definition of congruence in terms of rigid motions to show that two triangles are congruent if and only if corresponding pairs of sides and corresponding pairs of angles are congruent (CDE 2013, 72).
Secondary Standards
- Build new functions from existing functions. [Linear and exponential; focus on vertical translations for exponential.] (F-BF.3) (CDE 2013, 92)
- F-BF.3. Identify the effect on the graph of replacing f(x) by f(x)+k, kf(x), f(kx), and f(x+k) for specific values of k (both positive and negative); find the value of k given the graphs. Experiment with cases and illustrate an explanation of the effects on the graph using technology. Include recognizing even and odd functions from their graphs and algebraic expressions for them. (CDE 2013, 92)
California Department of Education. 2013. California Common Core State Standards. Sacramento, CA: California Department of Education.
Alternative Means of Expression
The following options give educators and IEP teams viable alternative means of expression a student could use when showing their understanding of this big idea. Much of the initiative team’s approach to identifying options centered on developing or adopting performance tasks to show what assessment might look like for this big idea.
Remember, LEAs adopt their own policies related to how a student meets the requirements for graduation. Educators and IEP teams should explore these resources with knowledge of these local policies.
General Guidance with Selecting Options for this Big Idea
For Transformations and Congruence, students may verbally or in writing explain the congruence of shapes using rigid transformations. Tools such as GeoGebra or Desmos can aid students in measuring lengths, recognizing slopes of line segments, and creating additional lines and line segments on a coordinate plane. Students can annotate on their graphs the effects of transformations on their shapes. They also can complete a simplified number of coordinate transformations that alter the shapes and express these changes algebraically, using either speech or text.
Sample Coursework
Project Created Performance Task
Alternate Means of Expression Option 1 is a performance task created by the project team that represents a viable alternate means of expression a school, district, teacher, or IEP team could utilize as an assessment option for this big idea.
Performance Tasks
Alternate Means of Expression Option 2 represent either a single performance task or a set of performance tasks that have been curated from publicly available task repositories that can be used as a viable assessment option.
Card Sort
Alternate Means of Expression Option 3 represent either a single performance tasks or a set of performance tasks that have been curated from publically avaible task repositories that can be used as a viable assessment option.
General Instructions for Completing the Card Sort Independently
- Starting with a card from Set A: Begin by selecting a card from Set A.
- Find its matching card from Set B: Carefully examine the cards in Set B to identify the one that corresponds or matches with the card from Set A.
- Place cards side by side: As you make matches, place the paired cards side by side on a large sheet of paper. Avoid stacking them on top of each other so that you can easily see all your matches and make revisions if needed.
- Explain your thinking: After making a match, take a moment to clearly and carefully explain your thought process. You can do this by writing down your explanation, recording it on a device, or explaining it aloud to yourself.
- Repeat for Set C, D, etc. (if applicable): If the Card Sort includes an additional set of cards, repeat the above steps for this set as well.
Bring Your Own Task (BYOT)
A Call to IEP Teams
We want students’ IEP team members to share their ideas regarding viable alternative means of expression pertaining to this big idea for students with disabilities, including those eligible for the CAA, these teams serve. IEP teams can define viable alternative means of expression for an individual student with an IEP, as long as these mediums meet the local requirements of the coursework.
A Call to Content-based Educators
In addition to IEP teams, we know secondary teachers and district curriculum leads have a wealth of experience and ideas related to innovative ways to assess students’ understanding of this content. We are interested in sample alternative means of expression this community sees as viable assessments of this big idea.
Please use the entry boxes below to share these ideas.
Important Note —These assessment tools will not be shared outside the review of the initiative team and will remain the intellectual property of the users who have made this submission. Furthermore, feedback or comments from the initiative team will not be given to uploaded content, nor does uploading materials imply that the alternative means of expression strategy is a viable option for this big idea.
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