What is the area of the green rectangle, which has sides tangent to the incircle and circumcircle of a triangle with side lengths a, b, c.? (Write the answer as a multiple of a quotient of two elementary symmetric functions in a, b, c.)
A regular hexagon and two similar rectangles. What fraction is green?
Two large congruent rectangles share a vertex and contain two coloured rectangles. What is red : blue?
A unit square and a rectangle touching three square sides and passing through the midpoint of the upper side. What is the minimal blue area?
Three equilateral triangles share three vertices. What is blue : red?
A unit square and a rectangle. What is the blue area?
Three squares on a grid. What is the ratio of the areas red : green : purple?
A regular decagon and triangles from vertices and side midpoints. What fraction is red?
Two rectangles are at right angles and have equal area. Prove that the three black lines are parallel.
Two squares, a rectangle and a semicircle. What is yellow : green?