We continue our discussion of the metric system and SI units.

## More Conversions

Some of the more useful metric conversions are as follows:

1.)  1 mL (milliliter) of liquid has the volume of 1 cubic centimeter (cc).

2.)  1 mL (milliliter) of water has a mass of approximately 1 g (gram).

The mass of 1 milliliter of water is approximately 1 gram.

3.)  1 L (liter) of water has a mass of approximately 1 kg (kilogram)
The mass of 1 liter of water is therefore approximately 1 kilogram.

4.)  1 m3 (cubic meter) of water has a mass of approximately 1 t (metric ton).
There are 1,000 liters in a cubic meter, so the mass of 1 cubic meter of water is approximately 1,000 kilograms or 1 metric ton.

5.)  1 ha (hectare) is 10,000 m2 (square meters)
1 hectare is 10,000 square meters, equivalent to the area of a square 100 meters on a side. A U.S. football field is about 100 meters long, so imagine a square the length of a football field on each side, and that's 1 hectare.

## Approximate Conversion Factors from Inch-Pound to Metric Units

Approximate English-to-metric conversion factors for some common units, as well as more precise factors are provided in Table 1. Here, bold-faced values are exact numerical conversions. Be sure to understand when estimated values will do or if more precise conversions are necessary. If you guess that something is “about 100 yards away,” then it is “about 100 meters away.” If you need to know what is exactly 100 yards away, then one converts the measurement to 91.44 meters.