When a river flows, the strength or force of the river depends on how far the river falls vertically compared to how far it flows horizontally. Find the slope of the river shown to the right. (Hint: The slope of a river is positive.) A right triangle, superimposed on a the image of a hill with a river, with one leg of 372 feet, a second leg of 75 feet, and the river is the hypotenuse.