Area of Composite Plane Figures in Real Life

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SWBAT create their own irregular plane figures and use their knowledge of regular plane figures to discuss the properties their creation (including area) using proper mathematical terminology.

Big Idea

Can We Build It! The construction and deconstruction of composite figures.

Curriculum Reinforcer

10 minutes

The curriculum reinforcer, is a daily practice piece that is incorporated into almost every lesson to help my students to retain skills and conceptual understanding from earlier lessons. My strategy is to use Spiraled Review to help my students retain what they learned during the earlier part of the year. This will help me to keep mathematical concepts fresh in the students mind so that the knowledge of these concepts become a part of students' long term memories.


10 minutes

Our opening activity today will be a gallery walk. Each group of students in the classroom will be given a sheet of chart paper. They will write down everything they know about area and plane figures in a bulleted list. After they have completed their list, they will post it in an area that has be pre-designated by me. Then, I will give each group 1 minute to view each list posted around the room until they have viewed every list posted. The students are to take note of similarities and differences between their list and the lists of the other groups.

Instruction & Teacher Modeling

10 minutes

In today’s instructional piece, we will simply review yesterday’s lesson using the lists that the students created for the gallery walk activity that they completed during today’s opening exercise. The elements of this concept that I will be reviewing are as follows:

  • How do you decompose composite figures?
  • How do you find the missing sides of the regular figures found in a composite figure?
  • What methods can you use to find the area of a composite figure?


To review these elements, I will facilitate a discussion that will revolve around those items that the students themselves brought to light during the opening activity. During the facilitation of this discussion, I will be sure to fill in any gaps in conceptual understanding, that my students may have, as it pertains to area.

Try It Out

5 minutes

In the guided practice of this lesson, my students will complete two problems that involve finding the area of composite figures. These two problems will be presented in a manner that will allow my students to see how area applies to real life.

Independent Exploration

20 minutes

In today’s independent practice my students will further explore the concept of area. They will do this as a group exercise. First, the students will be broken up into random groups of 3. Each group will be presented with a different problem. Each group will be expected to solve their problem and prepare a brief presentation of that problem. I will give the groups 15 minutes in total to solve their problem and come up with the way in which they would like to present their problem to the class. The presentation must contain the following elements.

  • A visual of the area being solved
  • Step by Step documentation of how the problem was solved.
  • Step by step solution of the problem
  • Documentation of the regular polygons used to solve the problem
  • Documentation of the formulas used to solve the problem.


The problems that the students will be using for the independent exploration are attached to this section of this lesson.


Closing Summary

15 minutes

To close out this lesson, each group of three students will be given 3 minutes to present their problem to the class.


After the presentations have concluded, the students will answer one question that will be the ticket out the door.