Which activity best demonstrates that area is the product of side lengths?

• A. Creating a line graph of a rectangle's dimensions.
• B. Using algebraic equations to solve area.
• C. Find the area of a rectangle using unit squares and explain why it equals the product of the side lengths.
• D. Estimating area by counting squares around irregular shapes.

Answer: (C)

Understanding that area is the product of side lengths is best shown by tiling a rectangle with unit squares and explaining why the total number of squares equals length times width. When you lay out unit squares to fill a rectangle, you can count how many squares fit in each row (the width) and how many rows there are (the length). Multiplying these two counts gives the total number of squares, which is the area. This concrete counting makes the multiplication relationship visible: the rectangle’s area grows by the width in each row across all rows, so you get length × width.

The other options don’t demonstrate this directly. A line graph of dimensions doesn’t illustrate how area arises from multiplying side lengths. Solving area with algebraic equations shows the formula but doesn’t provide the visual/concrete justification that area equals the product. Estimating area by counting squares around irregular shapes focuses on approximation rather than the exact product relationship for rectangles.