Two squares and two given areas. What’s the total area?
The spotlight
A right triangle with two cevians. What’s the angle α?
The lemon slice
A semicircle is inscribed in a quarter circle. What is the minimal yellow fraction?
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?
Between the bars
Two parallel lines support two rectangles. Prove they have equal area.
Mount Fuji
An equilateral triangle inscribed in a circle is divided by a diameter parallel to one of its sides. What is the proportion light : dark blue?
The Magdeburg hemispheres
A square containing a circle and two semicircles, all three having the same radius. What fraction is purple?
Five unit squares inside a larger square. What is the total area?
The axe head
A tetrahedron with given vertex coordinates. What is its volume?
The sleeping bag
A semicircle containing a circle. One line segment is tangent to the circle and connects to the semicircle centre. The chord connects two tangency points. What fraction is blue?