Tangram & basic concepts of geometry
We are going to make a tangram set by folding, unfolding and cutting shapes out of a sheet of paper. We will be looking at some of the characteristics of these shapes, as well as the relationships between them.
Start with an ordinary rectangular sheet of copy paper. Fold the right side of the sheet of paper onto the bottom side .
You should have a four-sided shape called a trapezoid. It has one pair of opposite sides parallel ('bases'), the other two sides are not parallel ('legs') .
Cut the little rectangle that’s not covered up and discard it.
The remaining folded piece forms a triangle .
We call such a triangle :
- an isosceles triangle because it has two equal sides (sides that are of equal length).
- a right triangle because it has a right angle