14. Any right-angled triangle has the property that the sum of the areas of the squares whose sides are the lengths of the two legs is equal to the area of the square whose side is the length of the hypotenuse. This is the famous Pythagorean theorem, known in the West as the Pythagorean theorem. The Pythagorean theorem has a history of 4000 years, with hundreds of different proofs. The ancient Chinese mathematician Liu Hui from the Wei and Jin periods provided a simple and beautiful proof method as shown in the left figure below, and the right figure is a Liu Hui-style Pythagorean puzzle board designed based on this method:
The 5 pieces of the Liu Hui-style Pythagorean puzzle board can also be assembled into a parallelogram as shown in the right figure. If the lengths of the legs are 3 cm and 4 cm, respectively, then the perimeter of this parallelogram is $\qquad$ cm.
Analysis:
The top and bottom bases of the parallelogram are 5 units long. In the figure, the red and green triangles are the same, with a side ratio of $4: 5$, and the length of the hypotenuse is $5 \div 4 \times 5=6.25$ cm. Therefore, the perimeter of the parallelogram is: $(5+6.25) \times 2=22.5$ cm.