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

# Tag: pentagon

## The pentagon attack

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

## The three day stubble

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

## Mickey Mouse

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

## The outsider

A circle with an inscribed regular pentagon, a square and a triangle. Prove that the point lies on the circumference of the circle.

## Crazy frog

A regular pentagon, two semicircles and two chords. What’s the length proportion a : b?

## The pentagon push

Two regular pentagons share a vertex. What’s the angle α?

## The bishop’s hat

Two overlapping regular pentagons share two vertices. What fraction is the overlap area?

## Tympanum II

A regular pentagon with a diagonal. What is the top angle of the isosceles triangle?

## The tympanum

A regular pentagon with a diagonal and an extended side. What is the top angle of the isosceles triangle?