14. (15 points) A square is divided into 5 identical small rectangles (as shown in the figure). If the perimeter of each small rectangle is 120 cm, find the area of the original square.


【Analysis】Observing the figure, we find that the length of the small rectangle is 5 times its width, i.e., length $=5 \times$ width, and length + width $=120 \div 2=$ 60 cm. Based on this, we can calculate the length and width of the small rectangle, and then find the area of the square.

【Solution】According to the problem, we have
$$
\text { length }=5 \times \text { width, }
$$

length + width $=60$ cm,
the length of the small rectangle $=50$ cm, width $=10$ cm,
the area of the square: $50 \times 50=2500$ (square cm)
Answer: The original area of the square is 2500 square cm.