Mentor: We call a polygon with three sides a triangle. Does anyone know what we call a polygon with four sides?

Student: A square?

Mentor: Well, a square is a polygon with four sides, but we call the whole family of four-sided polygons quadrilaterals.

Student: So a square is a quadrilateral?

Mentor: That's right. Can you think of other things that have four sides?

Student: A diamond--like the kind that you draw or a baseball diamond. They have four sides. Does that mean that a baseball diamond is a quadrilateral?

Mentor: Very good! That certainly is a quadrilateral.

Student: A door is a quadrilateral because it has four sides.

Mentor: Yes, any more?

Student: A piece of paper is a quadrilateral!

Student: A book!

Student: A computer monitor!

Student: A chess board or the chalk board!

Mentor: These are all wonderful answers. We should see how many quadrilaterals we see in our school and at home today.

Now we can talk about parallelograms!

Please direct questions and comments about this project to Addison-Wesley math@aw.com
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