Parallelograms in Action

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SWBAT apply key properties of parallelograms to applied problems, prove that diagonals in parallelograms bisect each other and learn about special cases of parallelograms like squares, rhombi and rectangles.

Big Idea

Students persevere through challenging problems that use properties of parallelograms and derive characteristics of special cases of parallelograms like squares, rhombi and rectangles.

Do Now

10 minutes

In this Do Now, students will show that they understand the key properties for a parallelogram.  This is a great formative assessment for students' knowledge of parallelograms, and also could be used as a short quiz. 

Pair-Share and Practice

25 minutes

Special Cases of Parallelograms

25 minutes

Students can work in pairs to brainstorm the characteristics of each special kind of parallelogram, and will use precise language (MP6) in order to distinguish and differentiate between the various shapes.   This activity requires students to make use and look for structure in comparing and contrasting these figures (MP7) - hopefully, this use of structure will allow students to see that a square is a special case of a rhombus, and other more intricate relationships between these shapes. In the student notes, there are websites provided for students to explore each kind of parallelogram using an applet, here is an example of the rectangle.

Activity/Homework and Exit Ticket

15 minutes

The activity/homework asks students to complete a proof and use algebra to find lengths of sides and diagonals in a parallelogram.  The last question asks students to make flashcards for the key vocabulary covered in today's lesson relating to square, rectangle, rhombus and parallelogram.  You can also ask students to create foldables (here is website about refoldables) or online flashcards at

The Exit Ticket asks students to compare and contrast shapes like rectangles and squares.  This exit ticket could be done as a turn and talk or also as a journal entry.