This puzzle is 25 square inches and is 1/4 inch thick! This classic puzzle forms a square and an equilateral triangle. It can also be used to explore the relationship between the area and the perimeter of regular polygons and more.
In addition to the basic Haberdasher Puzzle this puzzle can be used to explore a number of important ideas in geometry and other branches of mathematics. Here are some suggestions:
1) Use the set to explore congruent angles. Each of the four pieces has one right angle and three of the four pieces have a sixty degree angle. Both the sixty degree and the ninety degree angles can be proved by congruence combined with the observation that they will form a straight line.
2) Establish that any configuration of the four pieces produces the same area. Follow this by exploring the relationship between area and perimeter. Students can approximate the perimeter by actually measuring the respective configurations. Ask the students to make a conjecture about the perimeter as the number of sides (regular polygons) increases. You might ask the students what shape is approached as the number of sides becomes very large.
3) This puzzle now leads us to observe that the perimeter decreases toward a limit. The circumference of a circle of equal area establishes the lowest possible perimeter. So, we have moved from forming a square and an equilateral triangle to introducing the concept of a limit.
4) Please share with us any other applications you find for this particular puzzle!
If you like this puzzle, check our resource page for books by Greg Frederickson!
All of the plastic sets are excellent for use on overhead projector as well as tabletop.
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Includes solution and support material
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CD#3: Dissection Puzzle CD
The New Dissections Puzzle CD provides the user with full size templates of all of our dissection puzzles including tangrams. The templates include basic outlines and puzzle solutions. They can be used to create paper/laminated paper copies of the puzzles and/or to provide students with varying levels of support.
- Isosceles Right Triangle
- Haberdasher Puzzle
- Square to Pentagon
- Square to Hexagon
- Dissection Set
- Tangrams-Laser Cut
All A+ Compass tools are intended for use by adults and supervised children eight years old and up. Plastic and metal objects should not be placed in mouth and are intended for instructional use only.