A quarter circle with two chords of given length. What is the area of the orange quadrilateral?
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The quarter trampoline
Tag: quadrilateral
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Sailing by night
A circle with an inscribed quadrilateral. Prove that ab=cd. Kindly provided by Marshall W. Buck.
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The manta ray
A quadrilateral with connected side midpoints. What’s blue : red : yellow?
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Crossing mountains
A rectangle with four line segments. What’s brown : blue?
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The side mirror
An isosceles triangle and an external point with three line segments. Prove that the red points form a cyclic quadrilateral.
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The inner parallel
A cyclic quadrilateral with its diagonals and two altitudes. Prove that AB is parallel to EF.
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Ceteris paribus
Three circles with their centres and a triangle ABC. Given that D is the midpoint of BC, prove that quadrilateral ABEF and triangle ECF have both equal perimeter and equal area.
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The hand fan
Three congruent triangles constitute a quadrilateral. What’s red : blue?
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The queen
A cyclic quadrilateral with extended sides and two tangents forming an angle γ. What is γ in terms of α and β?
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The leftward lean
Two triangles form a quadrilateral. What’s the total orange area?