GED Math Practice Test

A kilometer is a unit of length that is equal to 1,000 meters. This is defined in the metric system, where the prefix "kilo-" means one thousand. Therefore, when converting kilometers to meters, you simply multiply the number of kilometers by 1,000. In this case, one kilometer is equivalent to 1,000 meters, making the correct answer D. This conversion is fundamental to understanding lengths and distances in metric measurements, which are commonly used in many parts of the world. The other options do not reflect the correct conversion and do not adhere to the metric system's definitions.