# Ch 23: 3rd Grade Math: Symmetry, Similarity & Congruence

### About This Chapter

## Symmetry, Similarity and Congruence - Chapter Summary

This Symmetry, Similarity and Congruence chapter teaches these concepts to 3rd grade students in an engaging format. The video lessons teach students to identify perpendicular and parallel lines as well as the congruence of rectangles, squares and other shapes. The assessment quizzes can be used to measure students' progress.

## Chapter Lessons and Objectives

Lesson | Objective |
---|---|

The Line of Symmetry in Geometric Shapes | Students can apply what they learn about the symmetry of squares, rectangles and other shapes. |

Congruence in Geometric Shapes | Instructors teach students to determine the congruence of various shapes. |

Similarity in Geometric Shapes | Students are taught to recognize likenesses in parallelograms, squares and other geometric shapes. |

Parallel, Perpendicular and Transverse Lines | Teachers explain the definitions and characteristics of these types of lines. |

Identifying Parallel Lines in Geometric Shapes | During this lesson, students can demonstrate their knowledge of parallel lines in rectangles, squares and parallelograms. |

Constructing Perpendicular Lines | Instructors teach elementary school students to illustrate perpendicular lines. |

Identifying Perpendicular Lines in Geometric Shapes | In this lesson, students can apply what they learn about perpendicular lines by working with rectangles, triangles, squares and trapezoids. |

Reflection, Rotation and Translation | Instructors teach these concepts in this lesson. |

Reflecting Simple Shapes in a Mirror Line | Teachers explain this process to students. |

Line and Rotational Symmetries of 2D Shapes | Students have opportunities to apply what they've learned. |

### 1. What is a Line of Symmetry in Geometric Shapes?

After viewing this lesson, you should be able to identify shapes that have a line of symmetry in them and know how to find where this line is. A short quiz to test your knowledge will follow the lesson.

### 2. Congruence in Geometric Shapes

Watch this video lesson to learn how you can determine whether two shapes are congruent or not. You will learn what the one criterion is when determining congruency between two shapes.

### 3. Similarity in Geometric Shapes

View this lesson to learn how you can determine whether shapes are similar. Find out how to use the one rule that tells you when your two shapes are geometrically similar.

### 4. Parallel, Perpendicular and Transverse Lines

What are the different types of lines? Where are they visible in the real world and how can you recognize them? Find out here and test your knowledge with a quiz.

### 5. Identifying Parallel Lines in Geometric Shapes

Watch this video lesson to learn how you can spot parallel lines in a rectangle, in a square, and in a parallelogram. You will learn how many pairs of parallel lines each of these shapes has.

### 6. Constructing Perpendicular Lines in Geometry

In this video lesson, you will see how to use geometric construction to draw perpendicular lines. Learn why geometric construction is useful. Also find out the only two tools in addition to your pencil that you need to do this.

### 7. Identifying Perpendicular Lines in Geometric Shapes

Do you know what a perpendicular line is? Do you know how to spot one in a geometric shape? This lesson will tell you how to spot perpendicular lines in squares, rectangles, triangles, and trapezoids.

### 8. Reflection, Rotation & Translation

This lesson will define reflection, rotation, and translation as they relate to math. It will also show you an example of each one so that you can perform these transformations on your own.

### 9. Reflecting Simple Shapes in a Mirror Line

What is reflection? How can we reflect a shape over a line? You will learn about this as well as about the important properties of reflection as it relates to math!

### 10. Line and Rotational Symmetries of 2-D Shapes

One of the most important concepts in geometry is the idea of symmetry. But what does it actually mean? This lesson explains the difference between line symmetry and rotational symmetry.

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### Other Chapters

Other chapters within the 3rd Grade Math: Practice & Review course

- 3rd Grade Math: Number Sense & Arithmetic
- 3rd Grade Math: Number Properties
- 3rd Grade Math: Solving Math Word Problems
- 3rd Grade Math: Estimation & Rounding
- 3rd Grade Math: Addition
- 3rd Grade Math: Subtraction
- 3rd Grade Math: Multiplication
- 3rd Grade Math: Multiples of Whole Numbers
- 3rd Grade Math: Multiplication Skills Practice
- 3rd Grade Math: Division
- 3rd Grade Math: Division Skills Practice
- 3rd Grade Math: Simplifying Whole Number Expressions
- 3rd Grade Math: Basic Algebraic Expressions
- 3rd Grade Math: Writing Algebraic Expressions
- 3rd Grade Math: Data & Graphs
- 3rd Grade Math: Probability & Statistics
- 3rd Grade Math: Units of Measurement
- 3rd Grade Math: Introduction to Geometric Figures
- 3rd Grade Math: Angles
- 3rd Grade Math: Triangles
- 3rd Grade Math: Quadrilaterals
- 3rd Grade Math: Perimeter, Area & Volume
- 3rd Grade Math: Fractions
- 3rd Grade Math: Decimals
- 3rd Grade Math: Money
- 3rd Grade Math: Time