A square containing five other squares. What fraction is coloured?
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Pandora’s box
Month: March 2021
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Hold the line
Two squares and two equilateral triangles. Prove the three points are collinear.
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Another brick
A rectangle and a quarter circle. What is the area of the rectangle?
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The Common Snowdrop
A square contains a smaller square. Their vertices are cyclically connected as shown, forming four triangles. What is the minimal green area fraction?
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The arena
In a circular arena two contestants are leaving from points A and B. Their respective speeds are such that they would collide at point C, but just before they do they exchange directions. Then they hit the edge of the arena and return to their starting points. During the whole race, A and B move at constant but not necessarily equal speeds. Which contestant returns to his starting point first?
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The chef’s hat
Two regular hexagons connected by a rectangle. Prove that the five vertices lie on a circle.
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The owl of Athena
A triangle with a median and another cevian. Two areas are given. What’s the total area?
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The delta wing
A triangle with a cevian. Two lengths are given. What length is x?
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One for Pi-less Day
A quarter circle inscribed in a unit circle. What’s the orange area?
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The Lion King
Three unit squares form the skeleton of a hexagon. What’s the area of the yellow rectangle?