Lesson 12 Rectangles with the Same Area

    • Let’s explore rectangles with the same area.

Warm-up Number Talk: Divide in Parts

Find the value of each expression mentally.

Activity 1 Area of 24

  1. Draw as many different rectangles as you can with an area of 24 square units.

  2. Find the perimeter of each rectangle you draw. Explain or show your reasoning.

Activity 2 Same Area, Different Perimeter

Your teacher will give you some paper for drawing rectangles.

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

    1. 12 square units

    2. 20 square units

    3. 42 square units

    4. 48 square units

    5. Choose your own area.

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

  3. Gallery Walk: As you visit the posters, discuss something you notice and something you wonder.

Practice Problem

Problem 1

Draw two rectangles on the grid with area 30 square units whose perimeters are different. What are the perimeters of your rectangles?