Answer
$$198 km = 1.98\times10^7 cm$$
Work Step by Step
To convert from km to cm, we can first convert kilometers to meters.
1 km = 1000m
198 km = 198000 m
Now we can easily convert meters to centimeters.
1 m = 100 cm
198000 m = 19800000 cm = $1.98\times10^7 cm$
