Convert 21 Millimeters to Kilometers
How long is 21 millimeters? How far is 21 millimeters in kilometers? 21 mm to km conversion.
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21 Millimeters =
0.000021 Kilometers
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Result in Plain English
21 millimeters is equal to exactly 21 millionths of a kilometer.
In Scientific Notation
21 millimeters
= 2.1 x 101 millimeters
= 2.1 x 10-5 kilometers
Millimeters
A millimeter, or millimetre, is a unit of length equal to one thousandth of a meter.Abbreviation: mm
Kilometers
A kilometer, or kilometre, is a unit of length equal to 1,000 meters, or about 0.621 miles. In most of the world, it is the most common unit for measuring distance between places.Abbreviation: km