These Triangle-counting Fun-Pages are made for you!
And now available as a book in CreateSpace by the name
You can download or copy from this place PDF-s of printable
worksheets of certain shapes & find by yourself how many
triangles are there?
If you would like to know the methods of
solving them, you should buy the full e-book:
These riddles are surveyed in the book:
and there will be more…