Area Measurement of Squares and Rectangles

Area in Grade 5 is formalized with the rectangle formula A = l x w. Students who have tiled areas concretely in Grade 3 now see the formula as a summary of that process: instead of counting every tile, multiply the number of rows by the number of columns. The key investigation is the relationship between area and perimeter: two rectangles with the same perimeter can have very different areas, and vice versa. Traditional rectangular dwelling design often optimizes one or both.