Five squares in a configuration. What’s the angle α?
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Movie film II
Author: Rik D. Tangerman
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Roll over Beethoven
Two regular hexagons share a vertex. If the red hexagon has area 4, what is the area of the blue one?
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Wrapping presents II
Six squares are placed around a triangle. What is the angle α?
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Off the grid
A square on a grid containing a red triangle with an extended side. What is the red fraction?
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The mirror dome
A ray of light is emitted from a point on the wall of a mirror-covered semicircle and reflects four times as shown to return to the same spot. If the radius is 1, what is the length of the path?
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Folded napkin II
A unit square paper is folded as shown. What is the red area?
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Tip the scale
Two equilateral triangles and a square. What’s the angle α?
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The cheese dome
A semicircle and two tangent circles (tangency point shown). What is the angle α?
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Half right
A right triangle with two angle bisectors. What is red : blue?
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Your turn
A regular hexagon of which the centre is a vertex of an equilateral triangle. What is the angle α?