# Lesson 11 Rectangles with the Same Perimeter

Let’s explore rectangles with the same perimeter.

## Warm-up Number Talk: Multiply to Divide

Find the value of each expression mentally.

## Activity 1 Perimeter of 16 Units

Draw as many different rectangles with a perimeter of 16 units as you can.

Calculate the area of each rectangle you draw. Explain or show your reasoning.

## Activity 2 Same Perimeter, Different Area

Your teacher will give you some dot paper for drawing rectangles.

For each of the following perimeters, draw 2 rectangles with that perimeter but different areas.

12 units

20 units

26 units

34 units

Choose your own perimeter.

Cut out 1 or 2 rectangles you want to share and put them on the appropriate poster. Try to look for rectangles that are different from what other groups have already placed.

Gallery Walk: As you visit the posters with your partner, discuss something you notice and something you wonder.

## Practice Problem

## Problem 1

Draw two rectangles with perimeter 20 units on the grid whose areas are different. What are the areas of the rectangles?