Categories

## The three rights

A trapezium containing three right angles is split in two. What is the proportion of the areas yellow : blue?

Categories

## The fallen pine

Two congruent isosceles triangles and three lines. Prove triangle AEF is also isosceles.

Categories

## The color fan

Two congruent rectangles share a vertex. Given that the three coloured areas are equal, what is the width x?

Categories

## The right angle

Two triangles inside a quarter circle. What is their area proportion?

Categories

## The triangle quartet

A square is divided into four triangles. The red area equals the blue area. What is the angle α?

Categories

## The corner stone

Four squares inside another square. What fraction is yellow?

Categories

## The bigger picture

In a small square two perpendicular lines are drawn. A larger parallel square is constructed as shown. Prove it is a scaled copy of the smaller square but rotated 90° anticlockwise.

Categories

## La Flèche Wallonne

A triangle is divided in four. What is the black area?

Categories