# Lesson 15

## Warm-up: What Do You Know About Area and Perimeter? (10 minutes)

### Narrative

The purpose of this What Do You Know About is to invite students to share what they know about and how they can represent area and perimeter.

### Launch

• Display the words area and perimeter.
• “What do you know about area and perimeter?”
• 1 minute: quiet think time

### Activity

• Record responses.
• “How are area and perimeter different?”

### Student Facing

What do you know about area and perimeter?

### Activity Synthesis

• “What strategies do you have for finding the area of a shape and the perimeter of a shape?” (To find the area of a rectangle, I multiply the side lengths. For perimeter, I just add up all the side lengths. I like to check for sides that are the same length because then you can multiply or make the calculation easier.)
• “What connections do you see between different answers?”

## Activity 1: Create Your Own Robot (35 minutes)

### Narrative

The purpose of this activity is for students to draw rectangles with specified perimeters to create their own robot. Students practice with perimeter and also find the area of their robots’ body parts in preparation for discussion during the gallery walk, which centers around the different areas that can be created with rectangles that have the same perimeter. Students can choose to work independently, with a partner, or in a small group.

MLR8 Discussion Supports. Before presentations begin, remind students to use words such as area, perimeter, units, and square units.
Engagement: Develop Effort and Persistence. Chunk this task into more manageable parts. Check in with students to provide feedback and encouragement after each chunk.
Supports accessibility for: Social-Emotional Functioning, Organization

### Required Materials

Materials to Gather

Materials to Copy

• Square Dot Paper Standard

### Required Preparation

• Students will need to tape together at least 2 sheets of the square dot paper to have space for their robot.

### Launch

• Groups of 1–4
• “Take a minute to read the directions for creating your own robot out of rectangles.”
• 1 minute: quiet think time
• Give each student 2 sheets of dot paper and a piece of tape. Have them tape the sheets together.

### Activity

• 20–25 minutes: independent, partner, or small-group work time

### Student Facing

1. Create your own robot with these specifications. Explain or show your work so it is clear your robot meets the required specifications.

1. Each body part must be a rectangle.
2. Head: perimeter of 36 units
3. Neck: perimeter of 8 units
4. Body: perimeter of 64 units
5. Each arm: perimeter of 24 units
6. Each leg: perimeter of 32 units
7. Include one more rectangular feature of your choice on your robot.
2. Find the area of each of your robot’s body parts.
3. Find the total area of your robot.
4. Gallery Walk: As you visit the robots with your partner, discuss the different areas that can be created with rectangles that have the same perimeter.

### Activity Synthesis

• Display the robots around the room.
• Have half of the students stand at their robot to share their ideas or answer questions as the other students visit their robot.
• Have the other half of the class visit their classmates’ robots with a partner.
• 5 minutes: partner work time
• Switch student roles and repeat.

## Lesson Synthesis

### Lesson Synthesis

“Over the last three lessons we’ve used shapes, perimeter, and area to design fabric patterns, parks, and robots. What are some other things you are interested in designing that could use shapes, perimeter, and area?” (I would like to design a building which would use lots of different shapes, perimeter, and area. I would like to design cars which would involve curved shapes that are solid. I would like to design clothing which would involve shapes and area.)

## Student Section Summary

### Student Facing

In this section we reasoned about shapes to design wax prints, a park, and a robot.

Also, we solved problems involving area and perimeter.