Answer:
The correct ones:
1.7 cm = 17 mm
345 meters = 0.345 kilometer
1.25 kilometers = 1,250 meters
Step-by-step explanation:
There are 1000 millimeters = 1 meter
so
4.7 m = 4.7 meters * (1000 millimeters/1 meter) = 4,700 mm not 47,000
343 m * 100 cm /1 m = 34,300 cm not 34.3 cm
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1.7 cm * 10 mm/1cm = 17 mm
345 m * (1 km / 1000 m) = 0.345 km
1.25 km * 1000 m/ 1 km = 1, 250 meters