Answer:
If you can't measure the length, breadth, or height of an item, you can utilise displacement or guesswork instead.
For example, you may calculate the volume of an item by measuring the displacement of water while it is submerged in it. You may then estimate its dimensions by assuming a certain form or by considering additional metrics such as weight or density.
Another technique is to estimate the object's dimensions using a known object of comparable size or visual cues such as a ruler or grid in an image. These procedures, however, may be less accurate and more prone to mistake.