Tag Archives: Polygons

Tangrams: A World of Geometry, Part Two

Tangrams: A World of Geometry, Part Two

I just realized that in my post two weeks ago, Tangrams: A World of Geometry, I only included part one of the tangram video. The forming of the pieces is completed in part two of that video. I’m hoping that some of you noticed that what you saw was not complete and that you were able to find part two on You Tube, but if not, you will find it here:

Notice in the part two video that after the seven pieces have been cut out, we can put them back together again to form the square we started with. We can also form a rectangle that is not a square, we can form a parallelogram, we can make a trapezoid, and we can also form another right isosceles triangle, using all seven pieces to make each shape.

A thread running through the geometry standard of Common Core is composing and decomposing geometric shapes. The tangram puzzle is a great way to give students lots of experiences with these ideas.

Actually, the polygons we formed in the video are only five the thirteen possible polygon shapes that can be made using all seven of the puzzle pieces. I should say that these polygon shapes are restricted to only those that have no dents-in. These are sometimes called convex polygons. If we allowed polygon shapes with dents-in, there would be many more that we could form. Click on each shape to download the full size image.

Polygon2   Polygon1

Above you see pictured two of the other eight polygon shapes that can be made. Attached to this post are two templates for these two shapes, sized to the piece of paper we used to make the puzzle. See if you can put the pieces together to form these shapes. Then try to find the other six shapes that can be made. If you find some of these other shapes, share what you found by way of commenting on this post.

Click here for “Tangrams: A World of Geometry, Part One”.