Categories
Intermediate

Marble box II

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

Categories
Beginner

Out of the box

Two squares and two given areas. What’s the total area?

Categories
Intermediate

The spotlight

A right triangle with two cevians. What’s the angle α?

Categories
Advanced

The lemon slice

A semicircle is inscribed in a quarter circle. What is the minimal yellow fraction?

Categories
Intermediate

Connecting the dots

Three squares share three vertices which form a right triangle. Their centres are connected to form another triangle of which one side is given. What’s the blue area?

Categories
Intermediate

Between the bars

Two parallel lines support two rectangles. Prove they have equal area.

Categories
Beginner

Mount Fuji

An equilateral triangle inscribed in a circle is divided by a diameter parallel to one of it’s sides. What is the proportion light : dark blue?