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
To measure the length of a hallway, you would typically use a measuring tool such as a tape measure or a measuring wheel. Start at one end of the hallway and extend the measuring tool to the other end, ensuring it is straight and taut for an accurate measurement. Record the measurement in the appropriate units, such as feet or meters, to determine the length of the hallway.
Milligrams, usually.
In SI units, use centimeters or meters. In non-SI units, use inches or feet.
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.
It would probably be miles.
inches in customary units
You would use square centimeters (cm^2) to measure the area of a rectangle that is 34cm in length.
Use Pythagoras' theorem to find the length of the 3rd side
You would use the unit of measurement "meters" to measure the length of a park bench.
It could be if you wished to use near-obsolete measurement units.
Volume of a rectangular block is: length*width*height. Use consistent units.
If you are able to use fractions - or smaller units - there is never a need to do so.