Categories
Intermediate

Triple dice

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

Categories
Beginner

The wall

Two congruent rectangles and squares. Proof that the four points are on one circle.

Categories
Advanced

The satellite

A circle containing three squares. What fraction is coloured?

Categories
Intermediate

The Lion King II

A regular hexagon and three squares. What is the proportion yellow : brown?

Categories
Beginner

The dangling square

Four squares and five shared vertices. If the orange area is 4, what is the green area?

Categories
Beginner

The yellow sailboat

A square, two equilateral triangles and an extended side. What is the proportion yellow : blue?

Categories
Beginner

Mondriaan II

A square contains three squares (black sides), one of which has an extended side (blue). What is the proportion yellow : blue?

Categories
Intermediate

Warning triangle II

A square, a triangle and two equal angles. What is the angle α?

Categories
Beginner

The inner sanctum

A square with four congruent equilateral triangles. What fraction is yellow?

Categories
Intermediate

Marble box II

Two squares, three circles and a common tangent. What fraction is coloured?