It depends on the spider - some Spiders can be measured in millimetres or centimetres; if you're thinking of tarantulas they could be measured in inches
If you mean what units, that would be meters.
Use Pythagoras' theorem to find the length of the 3rd side
In SI units, use centimeters or meters. In non-SI units, use inches or feet.
Milligrams, usually.
On many math test and quizzes it has been inches but normally they are made to fit inches in test so i would say it would be better to go with centimeters depending on what reason you need the units for.
There are no "following" units, but I would use metres.
The same units that you use for length and distance. For example, the SI unit would be the meter.
If you mean what units, that would be meters.
Meters.
You don't measure with length. You measure the length of an object with a ruler. You would use inches or metres as your units.
It would probably be miles.
You would multiply the length by the width.
inches in customary units
Use Pythagoras' theorem to find the length of the 3rd side
If you wanted to use English Units you would want to use feet or inches. If you wanted to use the metric system you would want to use centimeters.
Volume of a rectangular block is: length*width*height. Use consistent units.
It could be if you wished to use near-obsolete measurement units.