# MA.3.GR.1.3

Draw line(s) of symmetry in a two-dimensional figure and identify line-symmetric two-dimensional figures.

### Clarifications

Clarification 1: Instruction develops the understanding that there could be no line of symmetry, exactly one line of symmetry or more than one line of symmetry.

Clarification 2: Instruction includes folding paper along a line of symmetry so that both halves match exactly to confirm line-symmetric figures.

General Information
Subject Area: Mathematics (B.E.S.T.)
Strand: Geometric Reasoning
Date Adopted or Revised: 08/20
Status: State Board Approved

## Related Courses

This benchmark is part of these courses.
5012050: Grade Three Mathematics (Specifically in versions: 2014 - 2015, 2015 - 2022, 2022 and beyond (current))
7712040: Access Mathematics Grade 3 (Specifically in versions: 2014 - 2015, 2015 - 2018, 2018 - 2022, 2022 and beyond (current))
5012055: Grade 3 Accelerated Mathematics (Specifically in versions: 2019 - 2022, 2022 and beyond (current))
5012015: Foundational Skills in Mathematics 3-5 (Specifically in versions: 2019 - 2022, 2022 and beyond (current))

## Related Access Points

Alternate version of this benchmark for students with significant cognitive disabilities.
MA.3.GR.1.AP.3: Identify line-symmetric two-dimensional figures.

## Related Resources

Vetted resources educators can use to teach the concepts and skills in this benchmark.

## Formative Assessments

Identifying and Explaining Symmetry:

Students are asked to determine if lines drawn on two-dimensional figures are lines of symmetry and to explain their decisions.

Type: Formative Assessment

Using Lines of Symmetry:

Students are asked to use a line of symmetry to complete a drawing. Additionally, they consider how to describe a line of symmetry.

Type: Formative Assessment

Line Symmetry:

Students are asked to identify line-symmetric figures and then draw the lines of symmetry.

Type: Formative Assessment

Squares and Lines of Symmetry:

Students are asked to determine how many lines of symmetry a square has by drawing the lines of symmetry. Students then consider whether all quadrilaterals have four lines of symmetry.

Type: Formative Assessment

## Image/Photograph

Clipart: Geometric Shapes:

In this lesson, you will find clip art and various illustrations of polygons, circles, ellipses, star polygons, and inscribed shapes.

Type: Image/Photograph

## Lesson Plans

ABC Symmetry:

Students will explore the concept of line symmetry in this lesson. Students will explore two-dimensional pictures and decide whether or not each image has symmetry. Students will also fold pre-cut capital letters to decide whether or not each letter has symmetry.

Type: Lesson Plan

Symmetrical Solutions:

Students will use paper cutout and geoboards to find and create lines of symmetry. Students will have the opportunity to work with a partner and independently.

Type: Lesson Plan

## Original Student Tutorial

The Symmetry Sisters Save the Day:

Help the Symmetry Sisters save the City of Symmetry Line and the State of Arithmetic from the Radical Rat in this interactive tutorial!

Type: Original Student Tutorial

Lines of symmetry for triangles:

This activity provides students an opportunity to recognize these distinguishing features of the different types of triangles before the technical language has been introduced. For finding the lines of symmetry, cut-out models of the four triangles would be helpful so that the students can fold them to find the lines.

Lines of symmetry for quadrilaterals:

This task provides students a chance to experiment with reflections of the plane and their impact on specific types of quadrilaterals. It is both interesting and important that these types of quadrilaterals can be distinguished by their lines of symmetry.

Lines of symmetry for circles:

This is an instructional task that gives students a chance to reason about lines of symmetry and discover that a circle has an an infinite number of lines of symmetry. Even though the concept of an infinite number of lines is fairly abstract, students can understand infinity in an informal way.

## MFAS Formative Assessments

Identifying and Explaining Symmetry:

Students are asked to determine if lines drawn on two-dimensional figures are lines of symmetry and to explain their decisions.

Line Symmetry:

Students are asked to identify line-symmetric figures and then draw the lines of symmetry.

Squares and Lines of Symmetry:

Students are asked to determine how many lines of symmetry a square has by drawing the lines of symmetry. Students then consider whether all quadrilaterals have four lines of symmetry.

Using Lines of Symmetry:

Students are asked to use a line of symmetry to complete a drawing. Additionally, they consider how to describe a line of symmetry.

## Original Student Tutorials Mathematics - Grades K-5

The Symmetry Sisters Save the Day:

Help the Symmetry Sisters save the City of Symmetry Line and the State of Arithmetic from the Radical Rat in this interactive tutorial!

## Student Resources

Vetted resources students can use to learn the concepts and skills in this benchmark.

## Original Student Tutorial

The Symmetry Sisters Save the Day:

Help the Symmetry Sisters save the City of Symmetry Line and the State of Arithmetic from the Radical Rat in this interactive tutorial!

Type: Original Student Tutorial

Lines of symmetry for triangles:

This activity provides students an opportunity to recognize these distinguishing features of the different types of triangles before the technical language has been introduced. For finding the lines of symmetry, cut-out models of the four triangles would be helpful so that the students can fold them to find the lines.

Lines of symmetry for quadrilaterals:

This task provides students a chance to experiment with reflections of the plane and their impact on specific types of quadrilaterals. It is both interesting and important that these types of quadrilaterals can be distinguished by their lines of symmetry.

Lines of symmetry for circles:

This is an instructional task that gives students a chance to reason about lines of symmetry and discover that a circle has an an infinite number of lines of symmetry. Even though the concept of an infinite number of lines is fairly abstract, students can understand infinity in an informal way.

## Parent Resources

Vetted resources caregivers can use to help students learn the concepts and skills in this benchmark.

## Image/Photograph

Clipart: Geometric Shapes:

In this lesson, you will find clip art and various illustrations of polygons, circles, ellipses, star polygons, and inscribed shapes.

Type: Image/Photograph

Lines of symmetry for triangles:

This activity provides students an opportunity to recognize these distinguishing features of the different types of triangles before the technical language has been introduced. For finding the lines of symmetry, cut-out models of the four triangles would be helpful so that the students can fold them to find the lines.