Final answer:
To find the actual length of the road, multiply the length on the map by the scale factor and then convert to kilometers. The road is 2.1 kilometers long in reality.
Step-by-step explanation:
The student's question concerns converting a map scale to the actual distance on the ground. Here, the scale of the map is 1:30000, which means 1 cm on the map represents 30000 cm in reality. To find the length of the real road, we multiply the length of the road on the map by the scale factor. Since the map shows the road as 7 cm long, the actual length in centimeters is 7 cm × 30000 cm/cm = 210000 cm.
Now, notice that we are going from a smaller unit (centimeters) to a larger unit (kilometers), which means we will need to divide and move the decimal point to the left. There are 100,000 centimeters in a kilometer (100 cm in a meter and 1,000 meters in a kilometer means 100×1,000=100,000 centimeters in a kilometer), so we move the decimal point 5 places to the left, resulting in an actual road length of:
210,000 cm ÷ 100,000 cm/km = 2.1 kilometers.