Primary Type: Formative Assessment
Status: Published
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Resource ID#: 70640
Line Symmetry
Students are asked to identify line-symmetric figures and then draw the lines of symmetry.
Subject(s): Mathematics
Grade Level(s): 4
Intended Audience: Educators
Freely Available: Yes
Keywords: MFAS, symmetry, two-dimensional figures, line-symmetric figures, mirror
Resource Collection: MFAS Formative Assessments
ATTACHMENTS
MFAS_LineSymmetry_Worksheet.docx
FORMATIVE ASSESSMENT TASK
Instructions for Implementing the Task
This task should be implemented individually.
The teacher provides the student with the Line Symmetry worksheet and reads the following to the student:
Determine whether or not each shape has line symmetry. If the shape has line symmetry, draw a line of symmetry.
TASK RUBRIC
Getting Started
Misconception/Error
The student does not understand the concept of a line of symmetry.
Examples of Student Work at this Level
The student draws a line to divide each figure into two parts without regard to symmetry.
page 1 of 3 Questions Eliciting Thinking
What is a line of symmetry?
How can you determine if a line you drew is a line of symmetry? Do you know how to fold your paper to check if lines are lines of symmetry?
Can a figure have more than one line of symmetry?
If I drew a square, how many lines of symmetry would a square have? Where would the lines of symmetry be? Now if I drew an equilateral triangle, how many lines of
symmetry would there be? Where would the lines of symmetry be? How many lines of symmetry would an isosceles triangle have?
Instructional Implications
Provide instruction on the concept of a line of symmetry. Using one shape, show the student examples and nonexamples of lines of symmetry. Emphasize that a line of
symmetry divides a figure into two parts that are mirror images of each other. Provide the student with drawings of figures that can be folded along a given line to
determine if the line is a line of symmetry. Then have the student fold shapes to locate and draw lines of symmetry. Clarify the meaning of symmetry by explaining how
symmetric parts of a figure differ from parts with equal areas.
Consider using the MFAS task Identifying and Explaining Symmetry (4.G.1.3) to further assess the student’s ability to identify line­symmetric figures.
Making Progress
Misconception/Error
The student makes some errors in drawing lines of symmetry.
Examples of Student Work at this Level
The student appears to understand the concept of a line of symmetry and correctly draws some of the lines of symmetry but:
Is unable to locate a line of symmetry for one of the figures.
Incorrectly identifies the flag as having a line of symmetry.
Questions Eliciting Thinking
Good mathematicians check their work. Can you check to see that all of your lines of symmetry are correct?
What do the two halves made on either side of the line of symmetry have in common?
If you folded the flag (without rotating it), would the two pieces match up?
Instructional Implications
Provide the student with additional practice drawing and justifying lines of symmetry on two-dimensional figures.
Provide the student with a mirror. Have the student use the mirror to determine if a line drawn is actually a line of symmetry.
Provide additional practice through a symmetry sort. Provide the student with two-dimensional figures (some with lines of symmetry and some with lines drawn that are not
lines of symmetry). Have the student sort the line-symmetric figures and the other figures using a two-column table and then explain why the figures in each column show
lines of symmetry or no lines of symmetry.
Encourage the student to create his or her own line-symmetric shapes by folding a piece of paper in half and cutting a shape out. Then have the student darken the line
represented by the fold to reinforce that it is a line of symmetry for the shape.
Got It
Misconception/Error
The student provides complete and correct responses to all components of the task.
Examples of Student Work at this Level
The student correctly identifies all line-symmetric figures and correctly draws a line of symmetry through each.
Questions Eliciting Thinking
Do any of the figures have additional lines of symmetry you can draw?
page 2 of 3 How many lines of symmetry are in a circle?
Instructional Implications
Consider using the MFAS task Using Lines of Symmetry (4.G.1.3) to assess the student’s understanding of explaining, determining, and drawing lines of symmetry.
Consider using the MFAS task Squares and Lines of Symmetry (4.G.1.3).
Challenge the student to determine how many lines of symmetry there are in a circle. Guide the student to see that a circle has an infinite number of lines of symmetry and
each passes through the center of the circle.
ACCOMMODATIONS & RECOMMENDATIONS
Special Materials Needed:
Line Symmetry worksheet
Straightedge or ruler
SOURCE AND ACCESS INFORMATION
Contributed by: MFAS FCRSTEM
Name of Author/Source: MFAS FCRSTEM
District/Organization of Contributor(s): Okaloosa
Is this Resource freely Available? Yes
Access Privileges: Public
License: CPALMS License - no distribution - non commercial
Related Standards
Name
MAFS.4.G.1.3:
Description
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.
page 3 of 3