Twenty Questions Of Maddening, Delicious Geometry

For fans of geometry I can recommend the following book:

Apostol, Mnatsakanian: New Horizons in Geometry : https://www.amazon.com/Horizons-Geometry-Dolciani-Mathematic...

See also: https://en.wikipedia.org/wiki/Visual_calculus

Warning, the comments are spoilers in many cases. :(

These are awesome puzzles!

There are a few problems where I wish they'd be clearer about what the number labels mean. Areas? Edge lengths? They look like they're labeling areas, but I assume that figuring out what the numbers mean isn't intended to be part of the puzzle.

These would make excellent AMC problems. Visually pleasing diagrams, nontrivial uses of similarity, many problems having a “nice” and a “brute-force” solution–all of these fit right in.

Amazing presentation, and just the right difficulty. Thanks for posting this!

Are links to the answers provided?

Clever.

#3 was particularly elegant, once I saw the trick. I got x=5 for it.