# Lesson 4

Symmetry in Figures (Part 1)

### Lesson Purpose

### Lesson Narrative

This lesson introduces students to **symmetry** as an attribute of two-dimensional figures. Students relate **lines of symmetry** to the lines of folding that create two identical halves: if a figure is folded along or mirrored across such a line, the two halves would overlap and match exactly. The idea of folding along or mirroring across a line is essential here, as there are some figures that could be decomposed into two identical halves but have no line symmetry.

After reasoning about the meaning of lines of symmetry from examples and non-examples, students work to identify figures that have line symmetry and draw lines of symmetry.

- Representation

- MLR8

### Learning Goals

Teacher Facing

- Describe lines of symmetry for two-dimensional figures and identify figures with line symmetry.

### Student Facing

- Let’s describe symmetry in two-dimensional figures.

### Required Materials

Materials to Gather

Materials to Copy

- Shape Cards Grade 4
- Perfect Matches

### Required Preparation

Activity 1:

- Make copies of the set of figures in the second question available for cutting and for demonstration during the lesson synthesis.

Activity 2:

- Sort the shape cards from the previous lessons into three groups of 12 cards (A–L, M–X, and Y–JJ).

### Lesson Timeline

Warm-up | 10 min |

Activity 1 | 20 min |

Activity 2 | 15 min |

Activity 3 | 10 min |

Lesson Synthesis | 10 min |

Cool-down | 5 min |

### Teacher Reflection Questions

### Suggested Centers

- Which One? (K–5), Stage 4: Grade 3 Shapes (Supporting)
- Can You Draw It? (1–5), Stage 4: Area and Perimeter (Supporting)

### Print Formatted Materials

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Student Task Statements | docx | |

Lesson Cover Page | docx | |

Cool Down | Log In | |

Teacher Guide | Log In | |

Teacher Presentation Materials | docx | |

Blackline Masters | zip |