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Advanced

The orange pennant

A regular pentagon with two coloured triangles. What’s the proportion orange : blue?

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Intermediate

Getting stuck

A regular pentagon and a circle through two of its vertices and its centre. What’s the angle α?

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Beginner

Family ties

Two regular pentagons share a vertex. What is the proportion red : green?

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Intermediate

The antenna

A regular pentagon with an extended side. What’s the angle α?

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Advanced

It’s all right

A regular pentagon with a diagonal and a right triangle. What’s the angle α?

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Intermediate

A clear vision

A circle containing a regular pentagon and two equilateral triangles. All shown points are on the circle. What’s the angle α?

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Beginner

Projection bias

Two regular pentagons are placed side by side. What’s the proportion blue : green?

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Beginner

The pentagon attack

Two regular pentagons and two diagonals. What’s the angle α?

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Beginner

The three day stubble

A regular pentagon and a square share two vertices. What’s the angle α?

Categories
Intermediate

Mickey Mouse

Three regular pentagons and two extended sides. What fraction of the total area is red?