How many triangles are there?

The question is how many triangles are there in the following picture?

How many triangles?

I have thought to solve it by creating a formula based on the angles of the lines starting from the bottom of each side. I don’t get it right though. Any clues/ideas would be appreciated.


@Sp3000 is right, this is actually $PE-163$, and your particular case is given in the problem statement $ T(2) = 104.$

But if you are looking for a general formula to count the number of triangles in higher order then check here, (spoiler for the original PE problem).

Source : Link , Question Author : Dimme , Answer Author : Quixotic

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