Two semicircles with their centres. What’s the angle α?
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The double iglo
Tag: angle
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Missing an angle
A triangle with three line segments to an internal point. What’s the angle α?
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The mirror box
Light rays bounce off mirrored walls of a square before reaching one of the other corners. What are the slopes of the light rays leaving A that land in one of the corners B or D after exactly k=5 reflections?
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Making a dent
A right triangle with one trisected angle. What’s the angle α?
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Mix master
What is the sum of the angles at the blue vertices of this 11-gon?
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A central angle
One blue and two congruent red squares. The shown point is the red square centre. What is the angle α?
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The pumpkin
A regular hexagon and a circle centred in the blue point. What’s the angle α?
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Bottoming out
Two squares and a circle. What’s the angle α?
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Fan of cards
N coloured rectangular cards are arranged with a common vertex and common angle α between cards. If a single card has perimeter P, what is the perimeter of the coloured region, in terms of N, P, and α?
Extra condition: N and α are such that at least two edges of the bottom card are visible.
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Between the lines
Two coloured triangles share a vertex. Prove that the red line segments are parallel.