Two squares share a vertex. What is the proportion purple : green?
The green trap
A circle with its centre in the origin is cut by two parallel lines that are a distance d apart. One line is passing through the leftmost and one through the lowest point of the circle. What is the area of the green trapezium in terms of d?
The Holy Trinity
Three similar triangles are placed such that they form a large triangle. What is the proportion of line segments a : b?
The blue wink
A semicircle inscribed in a triangle inscribed in a semicircle. What fraction of the total area is blue?
Kindergarten
A circle with three tangents and two squares. The accentuated vertex is a tangency point. What’s the angle α?
Life is a dance
A quarter circle inside a square divides a line segment in parts of length 4 and 6. What is the square’s area?
Colour confinement
A semicircle with three tangent line segments. What is its area in terms of lengths a and b?
Two steps forward
Two equilateral triangles share a vertex and have their bases on the same line. A third equilateral triangle is constructed from their apexes. Prove that its apex is also on that line.
The earth projection
A circle touching a semicircle and a triangle. What is the proportion blue : green?
Crazy frog
A regular pentagon, two semicircles and two chords. What’s the length proportion a : b?