What Do You Notice? Quadrilaterals

Skills

Primary students (K-2): shapes

Intermediate students (3-5): classifying quadrilaterals

Mathematical Background

This graphic came from an article in an NCTM journal* and was labeled, "A classification of quadrilaterals". I removed the labels because the whole idea was to get participants to look for patterns in the shapes and classify them.

The graphic does a nice job of visually classifying quadrilaterals. A quadrilateral is a closed 2-dimensional figure made up of exactly four line segments. Inside the outer quadrilateral is a trapezoid, a quadrilateral with exactly one set of parallel sides. Then we have the parallelograms which are made up of two sets of parallel sides. Inside the green parallelogram on the right are the rhombuses. On the left are our rectangles. Notice how the square is both a rhombus and a rectangle.

*This is the graphic that I cut from the article and recently found it in my 'geometry' folder so I don't know which article or which Teaching Children Mathematics NCTM journal this came from.

Sample Student Responses

"There are 7 quadrilaterals."

"They all have 4 sides."

"There are 4 triangles in the space between the rhombus and the square."

"A square in a rhombus."