# Lesson 11

Rectangles with the Same Perimeter

### Lesson Purpose

The purpose of this lesson is for students to understand that rectangles with the same perimeter do not always have the same area.

### Lesson Narrative

In previous lessons, students learned to find the area and perimeter of rectangles. In this lesson, students draw rectangles with a specified perimeter, find their areas, and notice that rectangles with the same perimeter do not always have the same area. Students then draw rectangles with specific perimeter that have different areas.

• Engagement
• MLR8

Activity 2: Same Perimeter, Different Area

### Learning Goals

Teacher Facing

• Draw rectangles with the same perimeter and different areas.

### Student Facing

• Let’s explore rectangles with the same perimeter.

### Required Materials

Materials to Gather

Materials to Copy

• Square Dot Paper Standard

### Required Preparation

Activity 2:

• Create 4 visual displays. Each visual display should be labeled with a different perimeter. Use the following perimeters: 12 units, 20 units, 26 units, 34 units).
• Students cut out and tape their rectangles on one of the visual displays during this activity.

### Lesson Timeline

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

### Teacher Reflection Questions

Who has been sharing their ideas in class lately? Make a note of students whose ideas have not been featured in class and look for an opportunity for them to share their thinking in tomorrow’s lesson.

### Suggested Centers

• Can You Draw It? (1–5), Stage 4: Area and Perimeter (Addressing)