1. **State the problem:** We have a small rectangle with a height of 12 mm and an unknown width. Fourteen copies of this small rectangle are arranged in a larger rectangle composed of 3 rows: the top and bottom rows have 5 rectangles each, and the middle row has 4 rectangles. 2. **Understand the arrangement:** The total number of small rectangles is $5 + 4 + 5 = 14$. 3. **Determine the dimensions of the larger rectangle:** - The height of the larger rectangle is the sum of the heights of the 3 rows, so it is $3 \times 12 = 36$ mm. - The width of the larger rectangle is the width of the widest row. The top and bottom rows have 5 rectangles, so the width is $5 \times w$, where $w$ is the width of the small rectangle. 4. **Calculate the area of the larger rectangle:** The area is height times width: $$\text{Area} = 36 \times 5w = 180w$$ 5. **Find the width $w$ of the small rectangle:** Since the problem does not provide the width, we cannot find a numeric value for the area without it. However, if the width $w$ is known, the area is $180w$ square millimeters. **Final answer:** The area of the larger rectangle is $$180w$$ square millimeters, where $w$ is the width of the small rectangle.