A square with four congruent equilateral triangles. What fraction is yellow?
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The inner sanctum
Tag: triangle
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Triangle quartet II
Three coloured equilateral triangles share three vertices. Prove that the triangle formed by their centres is also equilateral.1This puzzle is also known as Napoleon’s Theorem.
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The spotlight
A right triangle with two cevians. What’s the angle α?
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Connecting the dots
Three squares share three vertices which form a right triangle. Their centres are connected to form another triangle of which one side is given. What’s the blue area?
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Mount Fuji
An equilateral triangle inscribed in a circle is divided by a diameter parallel to one of it’s sides. What is the proportion light : dark blue?
Five unit squares inside a larger square. What is the total area?
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The stained glass
Two congruent rectangles are placed side by side. Two line segments form two coloured quadrilaterals and three triangles. What is the proportion purple : green?
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Tilted hourglass II
Two equilateral triangles inside a square. What’s the proportion green : orange?
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The crazy diamond
Three rectangles and four triangles. Given that the red triangles have equal area, prove that the blue rectangles are similar.
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Surf the wave
A white triangle in a blue square. What is it’s top angle α?