Would you like to know how to build the biggest fort possible? Eric unveils the secret of building an unparalleled fort. Gather your cushions and get ready! It's not magic ... it's mathematical! Pedagogical side: Although there is a multiplicative relationship between the length, width and area of ​​a rectangle, the relationship between its length, width and perimeter is additive. There is no relationship between the area and the perimeter of a rectangle. In this segment, cushions are used to build a fort and to explore the notion of identifying the largest area for a fixed perimeter.