This lesson is optional because it does not address any new mathematical content standards. This lesson does provide students with an opportunity to apply precursor skills of mathematical modeling (MP4).

In previous lessons, students solved rectangular area problems. They connected area problems to multiplication. They learned that area is additive as they found the areas of figures composed of rectangles by decomposing them into non-overlapping rectangles.

In this lesson, students find unknown side lengths of a room and use their knowledge of the area of a rectangle to solve a problem about fitting a bed and a desk into a room. As students make decisions, they consider what space in the room is usable or what spot in the room is best for each piece of furniture.

What unfinished learning or misunderstandings do your students have about the areas of rectangles? How did you leverage those misconceptions in a positive way to further the understanding of the class?