At 03:44 PM 10/2/04 -0400, you wrote: >can anyone help??? > >how do u make a pentagon from 7 tangram pieces??????
Here's another pentagon.
Labeling the pieces as in my earlier post, place sides of 1 and 2 together oriented so that they form an isosceles right triangle. Now construct a trapezium. (I think that's the word for a quadrilateral with two opposite sides parallel and the other two sides equal but not parallel.) I have the long base of this figure on the bottom. Start on the left with 7, hypotenuse down. On the leg (right side) set the hypotenuse of 3. To the right of 3 place 4, sides together. Then a side of 5 against 4, with the other side continuing to extend the long base. Now place 6 against 5, continuing to extend the long base. Place this figure of five pieces against the hypotenuse of the original triangle, to extend the right side of the triangle. The sides and angles of the resulting pentagon are 1, 90 degrees, 3/2, 45 degrees, 5*2^2/4, 45 degrees, 1/2, 135 degrees, 2^2/4, 45 degrees.
Again, please ask if the construction isn't clear.