# Little Octagons To A Big Octagon

A decoupage problem consists of cutting up one figure in order to reassemble its pieces in the shape of another figure. A closely related problem is one of assembling, starting with several figures of identical shape and then cutting them into pieces as economically as possible in order to reconstruct a similar figure of greater size.

Can you cut these three little octagons into a total of ten pieces and then reconstruct a single octagon with three times the area?

## Solution

The dimensions of the little octagons must be multiplied by $\sqrt{3}$ in order to obtain the big octagon with three times the surface. It is therefore necessary to produce the hypotenuse of a right triangle with sides $\sqrt{2}$ and $\sqrt{1}$. The rest is inspired trial and error. (See Greg Frederickson, “More Geometric Dissections,” Journal of Recreational Mathematics [Summer 1974].)

### Posted by Edmark M. Law

My name Edmark M. Law. I work as a freelance writer, mainly writing about science and mathematics. I am an ardent hobbyist. I like to read, solve puzzles, play chess, make origami and play basketball. In addition, I dabble in magic, particularly card magic and other sleight-of-hand type magic. I live in Hong Kong. You can find me on Twitter` and Facebook. My email is edmarklaw@learnfunfacts.com

## 5 thoughts on “Little Octagons To A Big Octagon”

1. I’m not that good with this kind of puzzles. I prefer number and logic puzzles. It’s still a mystery how I learned the Rubik’s cube. :)