# Lesson 5

Some Triangles, All Triangles

### Lesson Purpose

The purpose of this lesson is for students to identify defining and non-defining attributes of triangles. Students draw triangles based on defining attributes.

### Lesson Narrative

In previous lessons, students used their own language, and continued to refine their language, as they sorted and identified shapes, including triangles, squares, rectangles, circles, and hexagons. They drew shapes based on attributes.

In this lesson, students analyze examples and non-examples of triangles and identify defining and non-defining attributes of triangles. Then, using dot paper, students draw different triangles.

- Representation

- MLR8

### Learning Goals

Teacher Facing

- Draw triangles based on their defining attributes.
- Identify defining and non-defining attributes of triangles.

### Student Facing

- Let’s explore what makes a shape a triangle.

### Required Materials

Materials to Gather

Materials to Copy

- Centimeter Dot Paper - Standard

### Required Preparation

Activity 1:

- Each group of 2 needs a set of Flat Shape Cards from a previous lesson.

Activity 2:

- Each group needs a set of Flat Shape Cards from the previous activity.

Activity 3:

Gather materials from previous centers:

- Geoblocks, Stage 3
- How Are They the Same?, Stage 1
- Compare, Stage 1
- How Close, Stages 1-3

### Lesson Timeline

Warm-up | 10 min |

Activity 1 | 10 min |

Activity 2 | 10 min |

Activity 3 | 20 min |

Lesson Synthesis | 10 min |

Cool-down | 0 min |

### Teacher Reflection Questions

Think about a time you recently made a mistake during math class. How did you leverage your mistake to show students that mistakes are just learning in process?