Two congruent circles and a right triangle inside a semicircle. What fraction is blue?
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The birdwatcher
Tag: triangle
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The tin foil hat
A circle inside a quarter circle. The triangle connects the two tangency points and the top of the quarter circle. What’s the angle α?
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The hammock
A square inscribed in a triangle. Two areas are given. What is the square’s area?
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The twin triangles
Two squares share a vertex. Prove that the red triangle is congruent to the blue one.
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Ice cube
A rectangle and a square. What is the proportion purple : blue?
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The hourglass
A rectangle with two crossing line segments. What’s the minimal shaded fraction?
Four quarter circles of radius 1, each containing a square. What is the blue area?
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Below the tree line
A triangle is split in two. What is the area of the green quadrilateral in terms of lengths a and b?
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Tympanum II
A regular pentagon with a diagonal. What is the top angle of the isosceles triangle?
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The ramp
A right triangle is split in two. What is the maximum yellow fraction?