As shown in the figure, it is known that the perimeter of three figures is equal, so find a: B: C. why

As shown in the figure, it is known that the perimeter of three figures is equal, so find a: B: C. why

Is it this graph? From this graph, we can establish a joint equation: 4B + a = 6A = 5C, express a and B with C, and get a = 5C / 6, B = (5c-a) / 4 = 25C / 24, so a: B: C = 20:25:24