There are 100 centimeters in a meter, and 1,000 meters in a kilometer. SO ...
(100 x 1000 = 100,000 cm) x 3 = 300,000 cm in 3 km
1 kilometer=100,000 centimeters
1 kilometer=100,000 centimeters
1 kilometer=100000 centimeters
1 kilometer=100,000 centimeters
1 kilometer=100,000 centimeters
1 kilometer=100,000 centimeters
1 kilometer=100,000 centimeters
1 kilometer=100,000 centimeters
1 kilometer=100,000 centimeters
1 kilometer=100,000 centimeters
1 kilometer=100,000 centimeters
1 kilometer=100,000 centimeters