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Beware of non-triangles

When you count triangles it is very important to avoid non-triangles.

It can be easily demonstrated in the first  stage of counting the basic shapes.

Look at this Pentagon, for instance: Green pentagram

The inner shape is also a Pentagon.

So, though there are 11 basic shapes

in it, but only 10 of them are triangles.

More than that:

When you stitch the inner Pentagon to

one of the triangles in the second phase

the shape is not a triangle also…

In short: beware!

This Pentagon riddle is solved in the book, of course.

Triangely yours

The Triangelog

New triangle-counting riddles

New in this site:

Two easy triangles-counting riddles:

Kite - basic shape

The Kite

and  The Trapeze



How many triangles can you find

in each one of them?

I think you will enjoy to sort & count the number of the triangles in them.

You can start by downloading the pdf-s in the worksheets page, printing etc…

Triangely yours


The Triangelog

P. S. Don’t forget to write me how many did you find…