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## House of Orange

A right triangle with a red and yellow square attached. Two circular arcs centered in the triangle vertices. What is the area of the orange rectangle in terms of red and yellow?

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## Out of proportion

An equilateral triangle containing a parallelogram, another equilateral triangle and a circular arc that is tangent in its base vertices. What is the proportion pink : blue?

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A unit square with an extended side immersed in another square. What is the area of the red triangle?

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## The framing effect

Four squares, three of which are coloured. What’s the area of the blue one?

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## Projection bias

Two regular pentagons are placed side by side. What’s the proportion blue : green?

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## Take five origami

Divide a rectangular piece of paper in five pieces of equal area. You only have a pair of scissors at your disposal, but you are allowed to make straight folds to guide you.

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## The voting pencil

A square and a rectangle share a vertex. Two triangle areas are given. What is the total area?

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## The red triangle

A square containing an isosceles triangle with given side lengths. What fraction is red?

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## Confined enclosure

A square containing four smaller squares. What fraction of its area is orange?

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## Check and balance

A square divided by three line segments. The red and blue areas are equal. What’s the length proportion a : b?