Final answer:
The real-life length of the river, with a map scale of 1:1000 and a map length of 7 cm, is 0.07 kilometers.
Step-by-step explanation:
The question asks us to find the real-life length of a river using a map scale of 1:1000, where the length on the map is 7 cm.
First, we must understand that a scale of 1:1000 means that 1 unit on the map represents 1000 units in real life.
So, if the map shows 7 cm, we need to calculate the actual length by multiplying 7 cm by 1000.
Conversion from cm to km: We know that 1 km = 1000 m and 1 m = 100 cm.
Therefore, 7 cm on the map is equal to 7,000 cm in reality. We need to convert this into kilometers.
7,000 cm = 70 m (since 1 m = 100 cm)
70 m = 0.07 km (since 1 km = 1000 m)
The real-life length of the river is therefore 0.07 kilometers.