Categories
Intermediate

The wall between us

Two circles inscribed an a trapezium divided by a perpendicular line segment. What is the proportion of its length a and the side b?

Categories
Intermediate

The minor chord

Three chords meet at the same point on the circumference of the circle. A perpendicular line segment divides one of them in two parts of length a and b. Express the length of the smallest chord x in terms of a and b.

Categories
Intermediate

The bubble chamber

A regular hexagon and two semicircles connecting vertices. What’s the angle α between the chords?

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
Intermediate

Black hole sun

A square containing two quarter circles and a common tangent. What is the proportion yellow : black?

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
Intermediate

The lunar twins

Three circles are tangent to each other. The black chords go through their tangency points. Prove that the red chord is a diameter of the largest circle.

Categories
Intermediate

The ocean view

Two squares of variable size share a vertex. What is the maximal blue fraction?

Categories
Intermediate

The green trap

A circle with its centre in the origin is cut by two parallel lines that are a distance d apart. One line is passing through the leftmost and one through the lowest point of the circle. What is the area of the green trapezium in terms of d?

Categories
Intermediate

The blue wink

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