Categories
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
Two medians and one side
A triangle has sides a,b,c and the medians d,e,f ending at those sides, respectively. Given only the lengths (b,d,e) construct the triangle (a,b,c). (Start with a triangle with side lengths determined in some manor from the given 3 lengths.)
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
Wings
Two wings are attached to the corner of a rectangle, and have corners lined up with the diagonal of the rectangle. The angles at the lower wing tips are equal. Must α = β at the left wing tips?
Categories
Video: The doubleganger
Categories
Triangle offspring
Four equilateral triangles. Prove that the three black line segments are concurrent.