Puzzling with Polygons: Warmup Problem

 

1.  Below is a right triangle.  Dissect it into three pieces so that you have 1 rectangle and 2 triangles.

 

 

 

2.  Now dissect this right triangle into three pieces so that you have 1 rectangle and 2 triangles—with one more condition: the three pieces can be reassembled to make a rectangle:

 

 

 

3.  Dissect this square into 4 triangles, which can be reassembled to make a non-square rectangle: