Answer:To convert kilometers to meters, you need to know that there are 1,000 meters in 1 kilometer.Here's the solution:Given:Value = 21 kilometersConversion factor:1 kilometer = 1,000 metersTo convert kilometers to meters, you multiply the number of kilometers by the conversion factor:21 kilometers×1,000 meters/kilometer=21,000 metersTherefore, 21 kilometers is equal to 21,000 meters.Step-by-step explanation: