Categories
Author: Rik D. Tangerman
Categories
Square offspring
Three squares and two line segments. What’s the angle α?
Categories
Video: No laughing matter
Categories
Squaring a rectangle II
A square contains a red rectangle with an extended side. Prove that red=|AB||AC|+|BE||CD|. By Matthew Arcus.
Categories
Video: Unring a bell
Categories
Pentagon offspring
Three regular pentagons are placed as shown. Prove that the three black line segments are concurrent.
Categories
Video: The doubleganger
Categories
Triangle offspring
Four equilateral triangles. Prove that the three black line segments are concurrent.
Categories
Video: Cherries
Categories
No laughing matter
Two squares share a vertex. Each square contains a coloured rectangle with extended side. What’s green : blue? By Matthew Arcus.