Take a sheet of A4 paper and place it in landscape format.

Fold up the bottom left corner as shown.

Now fold up the bottom right corner, again as shown.

What shape have you made?

What are the area and perimeter of this shape?

Take another sheet of A4 paper and place it in landscape format again.

Fold down the top left corner as shown.

Now fold up the bottom right corner, again as shown.

Finally fold down the top right corner as shown.

What shape have you made?

What are the area and perimeter of this shape?

What do you notice?