Squares
problem
Trig rules ok
Change the squares in this diagram and spot the property that stays
the same for the triangles. Explain...
problem
Folding squares
The diagonal of a square intersects the line joining one of the unused corners to the midpoint of the opposite side. What do you notice about the line segments produced?
problem
2001 spatial oddity
With one cut a piece of card 16 cm by 9 cm can be made into two pieces which can be rearranged to form a square 12 cm by 12 cm. Explain how this can be done.
problem
Square surprise
Why do you think that the red player chose that particular dot in this game of Seeing Squares?
article
Peg and pin boards
This article for teachers suggests activities based on pegboards, from pattern generation to finding all possible triangles, for example.
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Zooming in on the squares
Start with a large square, join the midpoints of its sides, you'll see four right angled triangles. Remove these triangles, a second square is left. Repeat the operation. What happens?