1. The problem presents a pyramid-shaped figure made of rectangles arranged in three levels. 2. The bottom level contains three rectangles; the middle rectangle is labeled with length $3.26$. 3. The second level contains two rectangles labeled $8.4$ (left) and $7.16$ (right). 4. The top level is a single rectangle without a label; we want to find its length. 5. Usually, in such pyramids, each upper-level rectangle length equals the sum of the two rectangles below it. 6. Therefore, the length of the top rectangle should be calculated as the sum of the two rectangles on the second level: $$8.4 + 7.16 = 15.56$$ 7. Hence, the top rectangle's length is $15.56$.