缩句:

The Mekong River is the longest of the three rivers, with a total length of approximately 4,350 kilometers (2,703 miles). The Irrawaddy River is the second longest, with a length of around 2,170 kilometers (1,348 miles). The Chao Phraya River is the shortest of the three, with a length of about 372 kilometers (231 miles).

In terms of size, the Mekong River is the largest in terms of both length and volume of water flow, followed by the Irrawaddy River and then the Chao Phraya River. These rivers play a crucial role in the ecosystems, economies, and cultures of the regions they flow through.

The Mekong River is the longest at 4,350 kilometers, followed by the Irrawaddy River at 2,170 kilometers and the Chao Phraya River at 372 kilometers. The Mekong River is also the largest in terms of volume of water flow, with significant impacts on the ecosystems, economies, and cultures of the regions it flows through.