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 just one example. We call the whole family of four-sided polygons quadrilaterals. 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!