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Advanced

The letter box

A rectangle with a diameter and two inscribed squares. What is its area in terms of the square areas A and B?

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Intermediate

Brothers in arms

The tangency points of two tangents of a circle are connected. Three perpendiculars are drawn from a point on the circle, of which two have a given length. What’s the proportion red : yellow?

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Beginner

The tornado

A quadrilateral covers exactly half of the area of a rectangle. Find the length x in terms of a, b and c.

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Intermediate

The steam iron

The midpoints of the hypotenuse of a right triangle and a line segment are connected. What is the length x?

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Beginner

David and Goliath

Two squares share a vertex. What’s the proportion blue : green?

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Intermediate

The major chord

A circle with four chords. What is the segment length x in terms of lengths a, b and c?

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Intermediate

The molecule

Three semicircles of which two centres are connected to corner points. What is the area X in terms of A and B?

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Advanced

A close encounter

Two semicircles are tangent to each other’s diameter. Are the line segments connecting their corners parallel?

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Intermediate

The hawfinch

An equilateral triangle with a circle tangent to two sides. The vertices are the tangency points. What is the length proportion of line segments x : y?

Categories
Beginner

The core business

Two squares with two highlighted vertices and a centre. Proof that these points are collinear.