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## 'Sticks and Triangles' printed from http://nrich.maths.org/

I made some triangles out of sticks. The sticks are all the same
length.

I can make a triangle out of three sticks:

What about four sticks? Five sticks? Six sticks?

I can make two different triangles out of ten sticks:

Can you find any others?

What about triangles made from twenty sticks?

What about all the lengths in between?

Can you make any rules about the numbers of sticks that make the
most triangles?