Metric system help? I don't understand it! ex: 43 centimeters=.00056 kilograms.Can someone please explain this stuff to me?? 1) 43 cm=____mm...

There is some confusion in the example of conversion of
metric system given in the question that is:

43 centimeters
= 0.00056 kilograms

Centimeter is a unit of length and
kilogram a unit of mass. These two do not have any standard conversion ratio. However in
specific cases an object with some par of it measuring 43 centimeter may weigh 0.00056
kilograms.

In general cases we can convert one unit in to
another only when both the unit measure the same
characteristics.

However I am giving below a general
discussion of conversion in metric system followed by answers to the conversions
required in the question.

Metric system is a decimal
system. This means that each unit is 10 times larger or smaller than the next unit for
the same characteristic.

Thus the basic unit for length is
meter. The next bigger unit for length is decameter that is equal to 10 meters and the
next smaller one is decimeter, which is equal to 1/10th of a
meter.

The basic unit of length in metric system is meter
and that for mass is gram.  Another unit in metric system is liter which is used for
measuring volume. In this way there are many basic units measuring different variables.
The other bigger or smaller units used are represented by standard prefixes attached to
the basic unit. These prefixes and their corresponding values are listed
below.

Prefix      Value Represented     
Examples

Kilo               1000                     
Kilogram (Kg), Kilometer (Km)

Hecto            
100                      Hectogram (Hg), Hectometer
(Hm)

Deca                10                      Decagram
(Dg), Dacameter (Dm)

Deci              
1/10                    Decigram (dg), Decimeter
(dm)

Centi             1/100                  Centigram
(cg), Centimeter (cm)

Milli               
1/1000                Milligram (mg), Millimeter
(mm)

Answers to the conversions required in the
question:

1) 43 cm = 430 mm
2) 721 km = 721000
m
3) 45.2 mg = 0.000452 hg (Hectograms)
4) 2 liters
=_____hg

Liters and hg (Hectograms) measure two different
characteristics. Therefore there is no standard conversion between them
5) 5.2
cl =0.052 l (liters)
6) 3.1 km = 310000 cm
7) .67 mg= 0.00067
g
8) .009 km = 9 m
9) 5.42 g = 0.0542 hg (hectogram)
10) 4
decimeters = 4 decimeters
11).0003 kl = 300 ml
12) 9,031 mm= 0.09031
hm (hectometer)