Can you turn this square into a rectangle? You might think it’s impossible, but it really isn’t. Here’s what you do. Divide the square into three parts A, B, and C. If you fit parts A, B, and C together like this, you can make a rectangle from a square.
Now try to make a triangle from this square. Divide the square into two parts A and B. Fit the parts together as shown below, and you can make a triangle from a square.
Make your own pattern out of construction paper or thin cardboard. Then, see how many other ways you can make a rectangle from a square, or a triangle from a square.