A ruler has length and therefore measures lengths not volumes.
The formula for the ruler method of volume is volume = length x width x height, where you measure the dimensions of the object using a ruler and multiply the three measurements together to calculate the volume.
A metric ruler measure a legth not a volume.
Ruler
you would use a ruler.
Volume of a rectangular solid. V = lwh
You don't
using a cubic ruler
A ruler is used to measure length and does not account for the height or width of an object, which are necessary to calculate its volume. To find the volume of a paperclip, you need to measure its dimensions in three dimensions using a tool such as a caliper or by using a water displacement method.
A ruler or tape measure would be the best tool. You cannot measure the volume directly. First, measure the length, width and height with the ruler and use the formula of volume of cubiod (L x W x H)
A ruler or tape measure.
When the object is a regular, geometric shape.