Categories
Beginner

The Sikh turban

A regular hexagon containing an orange quadrilateral. What fraction of the total area is blue?

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Intermediate

The honeycomb

Two regular hexagons inscribed in a square. If the hexagons have side length a and b, what is the square’s side length?

Categories
Intermediate

The folded napkin

A square sheet of paper is folded symmetrically from a corner. If the fold length is 4, what is the area of the triangle formed by the other three corners?

Categories
Intermediate

Together we stand

Two squares sharing a vertex. What’s the angle α?

Categories
Intermediate

The pleasure dome

A semicircle with three squares. The areas of the smaller squares are given. What is the area of the biggest one?

Categories
Beginner

Twin peaks

A rectangle with three line segments. What is the proportion yellow : red?

Categories
Intermediate

Pyramidion

A triangle containing a semicircle and an equilateral triangle. What fraction is golden?

Categories
Advanced

The ocean sunset

A semicircle is inscribed in a rectangle. What is the minimal covered fraction?

Categories
Intermediate

Triple dice

An equilateral triangle with three congruent squares. What’s the angle α?

Categories
Intermediate

Paper hat II

Two overlapping congruent right triangles. If |AB|=15 and |BC|=7, what is the total area?