Millimeters or centimeters.
Just look at it this way. More small toys can fit in a box than the number of big toys that can fit in a box. In units of measure meant there are a number of smaller units in a bigger unit. For example there are 100cm in a m and 100000cm in a km.
A2 has double the area of A3, with a width equal to the length of A3 and a length equal to double the width of A3
100 m long & 50 m width .
To measure the area of an arbitrary two dimensional shape you will use a planimeter. To measure an area you could also just use a simple ruler depending on how big the area is.
A centimeter is equivalent to 10 millimeters. It is approximately the width of a pinkie finger.
Inch, centimeter, or millimeter.
A micrometre. A millimetre would be too big a unit but a tenth of a millimetre should do fine.
Ok so if you have a tape measure open it and I will show you how it is used exactly. So as you can see at the top which are the big lines of the tape measure they are called (inches). This is used for measuring the formula of a arm size, hand size, hip size and the waist size. But now I will talk about measuring as assessing width as my measuring unit. So basically the top constituent part of the tape measure are the inches and the bottom are the cm's. So to find the width would mean that every 10 cm is the width but when go on to a quarter of width it will basically mean that the answer would be 1w and a quarter.
The size of the egg is not determined by how big or small it is. They are sized by the unit measure as a whole.
metres, kilometres .................................
Meters.
There is no equivalence. A microgram (mcg) is a measure of mass. Its only dimension is that of mass, not length or width. Any attempt at conversion from one to the other is not valid.
Any cubed unit depending on how big the rock is
It depends on how big the park is, it could be measured through feet, meters, or maybe even miles.
Cubic square feet is not a valid unit of measure. Feet is a measure of length.
Gallons.
Grams or Kilos depending on how big the melon is