A regular pentagon and two semicircles. Prove that they are orthogonal, i.e. the tangents in the intersection point are orthogonal.
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The crosshairs
Tag: angle
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Three times three
A regular nonagon and two equilateral triangles. What’s the angle α?
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The laser game
In an equilateral triangular mirror room a laser is shot from the top vertex down to the base. The light ray bounces three times to return to the same base point. What is the angle α?
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The vanilla ice cream
A regular pentagon with two extended sides and a right angle. What is blue : green?
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The falling pillar
Three congruent rectangles on a line. What’s the angle α?
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Guylines II
A square, two orthogonal axes and two angles. What’s the proportion α : β?
A triangle with two line segments. What’s the angle α?
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Angle chasing galore
Two intersecting circles with a triangle connecting them. Show that the three red points are collinear.
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Yeah, right!
A regular pentagon with three line segments. What’s the angle α?
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Pink parallels
A pink parallelogram with two extended sides. What’s α : β?