Determine the slope of the river, the length of which is 502 km, the height of the source – 256 m, the height of the mouth – 100 m.

The fall of the river is the excess of its source over the mouth, expressed in meters.
The slope of a river is the ratio of its fall (in cm) to its length (in km).
1) Find the fall of the river: 256 m – 100 m = 156 m
2) Find the slope of the river: 156 m: 502 km = 15600 cm: 502 km ≈ 31 cm / km
Answer: the slope of the river is 31 cm / km.

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