Complex sentence: The 922-kilometer southeastern side of the triangle is the land border with Nicaragua; it follows the Río Coco near the Caribbean Sea and then extends southwestward through mountainous terrain to the Gulf of Fonseca on the Pacific Ocean.
Split into simpler sentences: The 922-kilometer southeastern side of the triangle is a land border with Nicaragua. It follows the Río Coco near the Caribbean Sea and then extends southwestward through mountainous terrain to the Gulf of Fonseca on the Pacific Ocean.