An equilateral triangle inside a rectangle. What is red : yellow : blue?

# Tag: rectangle

## The basketball court

An orange circle is squeezed inside a rectangle. Show that no matter how the blue point moves on the circle, the derived points Q and P will satisfy |QL| = |KP|.

## Falling pillar II

Three congruent rectangles on a line. Prove that the four red points are cyclic.

## The falling pillar

Three congruent rectangles on a line. What’s the angle α?

## Night mountain

A rectangle containing three line segments. What fraction is blue?

## Corner to corner

A rectangle inside a rectangle. What is the green area?

## The ball pit

Two rectangles contain 6 congruent circles. The common rectangle side passes through the top centre. What’s yellow : red?

## Shine your light

A quarter circle of radius 1, a rectangle touching the circle in an arbitrary point and a yellow quadrilateral. What is the minimal perimeter of this quadrilateral?

## The small cog

Two circles, a rectangle and two line segments. Prove that the red points are collinear.

## The personal letter

Two rectangles share two vertices. What’s the green fraction?