# Challenge #1

• Oct 19th 2009, 02:57 AM
Prof Paulo
Challenge #1
The following figure is composed of 17 matches to form 6 squares geometrically similar to each other:

http://img.over-blog.com/300x207/0/3...//F-sforos.png

Remove only 3 matches in order to get only 4 squares geometrically similar to each other.

* Adapted from the book Distractions mathématiques (Montréal - 1977).

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• Oct 19th 2009, 03:26 AM
pankaj
If you remove the three horizontal sticks in the middle you do get four squares
• Oct 19th 2009, 07:43 AM
Soroban
Hello, Prof Paulo!

I don't trust the wording of this problem.
Besides, the solution is too simple.

Quote:

The following figure is composed of 17 matches to form 6 squares geometrically similar to each other.
Redundant . . . all squares are geometrically similar.

Code:

```      ----- ----- -----       |    |    |    |       |    |    |    |       ----- ----- -----       |    |    |    |       |    |    |    |       ----- ----- -----```

There are eight squares which are geometrically similar:
. . six 1-by-1 squares,
. . two 2-by-2 squares.

Quote:

Remove only 3 matches in order to get only 4 squares geometrically similar to each other.
Solution:

Code:

```      -----      -----       |    |    |    |       |    |    |    |       -----      -----       |    |    |    |       |    |    |    |       -----      -----```

Perhaps the author meant congruent squares?

• Oct 19th 2009, 12:49 PM
Prof Paulo
It's correct pankaj e Soroban!