# Designing a 3D Product in 2D: A Sports Bag

## Mathematical goals

This lesson unit is intended to help you assess how well students are able to:

• Recognize and use common 2D representations of 3D objects.
• Identify and use the appropriate formula for finding the circumference of a circle.

## Introduction

The lesson unit is structured in the following way:

• Before the lesson, students attempt the Designing a Sports Bag task individually. You review their work and formulate questions that will help students to improve their solutions.
• At the start of the lesson, students respond individually to the questions set. Then in groups, they combine their thinking and work together to produce a joint solution in the form of a poster.
• In the same small groups, students evaluate and comment on sample responses. They identify the strengths and mistakes in these responses and compare them with their own work.
• In a whole-class discussion, students explain and compare the strategies they have seen and used.
• Finally, students reflect on their work and their learning.

## Materials required

• Each student will need a copy of Designing a Sports Bag, some plain paper, a mini-whiteboard, a pen, and an eraser.
• Each small group of students will need a new copy of Designing a Sports Bag, some poster paper, a marker, and copies of the Sample Responses to Discuss. Provide calculators, rules, and squared paper for students who request them. An optional Formula Sheet is available for use as required.

## Time needed

25 minutes before the lesson, a 95-minute lesson (or two 50-minute lessons), and 15 minutes in a follow-up lesson. Timings are approximate. Exact timings will depend on the needs of your class.

## Mathematical Practices

This lesson involves a range of mathematical practices from the standards, with emphasis on:

## Mathematical Content Standards

This lesson asks students to select and apply mathematical content from across the grades, including the content standards: