Lesson 8

Encontremos el perímetro

Lesson Purpose

The purpose of this lesson is for students to find perimeters of shapes given all or some of the side lengths.

Lesson Narrative

In previous lessons, students learned about attributes of two-dimensional shapes. They also learned about perimeter and drew shapes with specific perimeters. In this lesson, students find perimeters of shapes given side lengths and use the attributes of shapes to find the perimeter given only some of the side lengths.
• Representation
• MLR8

Activity 1: Maneras de encontrar el perímetro

Learning Goals

Teacher Facing

• Find the perimeter of two-dimensional shapes given all or some of the side lengths.

Student Facing

• Encontremos el perímetro de más figuras.

Lesson Timeline

 Warm-up 10 min Activity 1 20 min Activity 2 15 min Lesson Synthesis 10 min Cool-down 5 min

Teacher Reflection Questions

How did students leverage their geometry knowledge about attributes of shapes to reason about perimeter in today’s lesson?

Suggested Centers

• Can You Draw It? (1–5), Stage 3: Grade 3 Shapes (Addressing)