Two semicircles and two congruent triangles with a side of length 2. What’s the brown area?
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The end of the tunnel
Tag: circle
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The rocking cradle
A semicircle and an interior circle are tangent to each other. The chord towards the tangency point is divided in segments of length 1 and 2. What is the pink area?
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Caught in the middle
Two circles support a triangle. Prove it is equilateral.
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The monk’s hood
Two similar triangles inside a semicircle. What’s the angle?
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Mars rover has landed
Two semicircles and two right triangles. What fraction of the large triangle does the small one cover?
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The observatory dome
A semicircle with a radius, a chord and an altitude. What is the angle?
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The PowerPoint
A point lies 8 from the centre of a circle of radius 6. The angle α is variable. What’s the maximum triangle area?
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The toucan
Two congruent right triangles inscribed in a circle. The circle centre lies on one of the hypotenuses. What’s the angle?
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The butterfly effect
Two touching circles and two lines passing through the tangency point. What is the area proportion of the two triangles?
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Don Quixote and the windmill
Don Quixote is approaching a windmill. The sails of length √2 are attached to a point that is 2 above eye level. What is the maximum vertical angle that Don Quixote perceives as he moves forward?