To begin this lesson, I have the students compare the attributes of a quadrilateral and a parallelogram. Because we have spent time on these shapes, I ask each student to work with a partner to find an example in the classroom for each of these shapes. The examples include erasers, books, desks, small boxes, and whiteboards. I also have the students draw an example of each of these shapes. During this comparison, I emphasize the quadrilateral form includes four sides but not parallel sides.
The definition of a parallelogram will include all sides the same length, different opposite angles, and both pairs of opposite sides are parallel.
I chose to have the students find examples to engage them in the lesson and to support other students that may still have some confusion about the differences in shapes. Using the examples from the classroom and drawing other examples supports students' understanding about these shapes.
During this lesson the focus will be on learning the attributes of a trapezoid, square, rectangle, and rhombus. Each of these shapes can be classified as quadrilaterals, and all are parallelograms except the trapezoid.
Trapezoids have one set of parallel sides. The rhombus has two sets of parallel sides with one set of opposite angles that are obtuse, and the other opposite angles are acute. The sides of a rhombus can be of equal lengths or different lengths. I have the students discuss the differences between rhombuses, squares and rectangles including focusing on the angles and the lengths of the sides. To demonstrate the angle sizes we use index cards for 90 degree angles. Our discussions include that an obtuse angle is larger than 90 degrees and an acute angle is less than 90 degrees.
To model some of this information for the students, I use a preprinted page from an old math series with shapes. This could also be completed through a word processing program or by using manipulative shape blocks. The students will be measuring the lengths of the sides with rulers in centimeters.
One of the most important connections students can make is between the content and the real world. This is aligned to the Common Core Standards. During this activity the students are looking for real life examples of shapes. The students create small scrapbooks including the definition of each of these shapes: quadrilateral, parallelogram, trapezoid, rectangle, square, and rhombus. The scrapbooks are created from white copy paper folded into a book (hamburger style).
Next, the students draw their own example of these shapes, or trace a shape using one of the math manipulative shapes. Finally, they cut out and include a real world example. These examples are found from old reference books or by using and printing Google Images. During my lesson this activity was supported by the technology teacher. Some students used the picture from the old math textbook to cut apart photographs such as the Eiffel Tower for the trapezoid. These photographs are glued into their scrapbooks. I want the students to use their final projects for a writing project as a cross-curricular lesson.
This may be a lesson that requires more than one day to implement so that students have a sufficient amount of time to locate examples, print, etc.