Categories
Beginner

Buddha’s belly

A square containing a quarter circle and a tangent line segment. What is a : b?

Categories
Advanced

The stuck boulder

A rectangle contains a circle wedged between two triangles. What is the circle radius in terms of triangle heights a and b?

Categories
Intermediate

The ball pool

A square having side length 12 contains a quarter, semi and full circle. The centres of the latter two are connected to the square’s centre to form a green triangle. What is it’s area?

Categories
Advanced

The Queen’s chamber

A right triangle with three squares forming a smaller inner triangle. What is the maximal blue fraction?

Categories
Beginner

The outsider

A circle with an inscribed regular pentagon, a square and a triangle. Prove that the point lies on the circumference of the circle.

Categories
Intermediate

My two cents

A right triangle is divided in two triangles, one of which is isosceles. The two inscribed circles are congruent. What is the total area?

Categories
Advanced

The Holy Trinity

Three similar triangles are placed such that they form a large triangle. What is the proportion of line segments a : b?

Categories
Intermediate

The blue wink

A semicircle inscribed in a triangle inscribed in a semicircle. What fraction of the total area is blue?

Categories
Advanced

Kindergarten

A circle with three tangents and two squares. The accentuated vertex is a tangency point. What’s the angle α?

Categories
Intermediate

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.