A rectangle is split by two perpendicular lines. The four circles pass through vertices and intersection points. Their centres form a purple quadrilateral. What fraction of the large rectangle area does it cover?
Two squares, three circles and a common tangent. What fraction is coloured?
A right triangle with two cevians. What’s the angle α?
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?
Two parallel lines support two rectangles. Prove they have equal area.
A tetrahedron with given vertex coordinates. What is its volume?
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?
Two equilateral triangles inside a square. What’s the proportion green : orange?
Two circles, four tangent line segments and a square. What’s the proportion red : blue?
Three rectangles and four triangles. Given that the red triangles have equal area, prove that the blue rectangles are similar.