Categories
Intermediate

The intersection

Two intersecting circles. Prove that the three blue line segments are of equal length.

Categories
Intermediate

All the marbles

A circle containing eight touching circles. Circles of equal colour are congruent. What fraction of the total area is coloured?

Categories
Beginner

The drunk spider

A circle with several chords forming four coloured triangles. What is the proportion yellow : purple?

Categories
Beginner

That hill

A triangle is divided in three smaller triangles. What is the proportion yellow : green?

Categories
Intermediate

Two square pegs

Two squares and a circle. What is the proportion a : b?

Categories
Advanced

Eye of the apple

A circle with an inscribed triangle with an inscribed circle. The centre of the large circle is on the small one. What fraction of the area is blue?

Categories
Intermediate

The other half

Three semicircles with diameters a, b and x. Express x in terms of a and b.

Categories
Beginner

The Gouda cheese

A quarter circle with two inscribed squares. What’s the angle α?

Categories
Beginner

Three squares a day

Three congruent squares inscribed in a rectangle. What fraction of the total area is green?

Categories
Advanced

The ice cream cone

A circle tangent to a triangle side and to the two other extended sides. What is its diameter?