Two rectangles are at right angles and have equal area. Prove that the three black lines are parallel.
Tag: area
A golden year
Two squares, a rectangle and a semicircle. What is yellow : green?
Decorating the tree
A symmetric tree has decorative lines of equal slope, and of lengths 11 and 13. What is the area ratio of green to red to brown?
The brick pile
Three congruent rectangles inscribed in a triangle. What fraction is brown?
Compartmentalization
A square with two circles and two common tangents. What’s red : blue?
Through the roof
A semicircle with its centre. What is green : red in terms of the angles α and β?
Lemon slice II
A semicircle inscribed in a quarter circle. What fraction is yellow?
Cuckoo in the nest
Two tangent semicircles inscribed in another semicircle. What is the total area?
Cozy in his chair
Orange and green semicircles with equally long but perpendicular diameters (both length 2) are partially covered by a blue canopy at angle α. What is the orange area, which is not covered by either of the other regions, in terms of α?
Stuck in the corner
A square with a diagonal and a right triangle. What fraction is red?