you would use the water displacement theory
The volume of the object.
To calculate the volume of an irregularly shaped object, a good idea would be to get a bucket full of water and submerge that object into the bucket. Then measure the amount of water that runs over and that should be the volume of your object. For example if you take a sealed bottle of bottle stick it in a bucket filled with water, then let it's volume filll the space and displace the water. The water that is displaced or the water that runs out is the volume of your irregular shape. Get it?
Phobos and Deimos are the two moons of Mars. They are small and shaped irregularly. The surfaces are scarred by many large impact craters. This is why the moons are extremely old.
I don't see why measuring the volume of liquids using the Eureka can method. It is an indirect measure -- you displace water or some other fluid to measure a liquid? A direct tool, such as measuring beakers or cylinders with markings, is inexpensive and can measure volume adequately. Eureka cans are more for measuring the volume of solids, especially irregularly-shaped ones. ===================================
You can read the measurements wrongly depending on the type of liquid used to measure the volume for irregularly shaped objects. You should determine whether the liquid used forms an upper or lower meniscus. For regularly shaped objects, errors occur when you read the units are rounded off.
Mr.Tomak is angry now.
The apple was irregularly shaped
Google "Archimedes' Principle" and see if that gives you a clue...
A balance is used to measure the mass of an irregularly shaped solid.
Using a graduated beaker, add water sufficent to totally immerse the object. Note the initial volume of the water without the object. Put the irregularly-shaped object in the beaker and note the final volume. The difference between the final and initial readings is the volume of the object. This is only possible if the object is not soluble in water. If it is, use some other fluid in which it is not soluble.
You can push it under water / under the liquid's surface, and measure the displacement of liquid.
The volume of an irregularly shaped solid can be measured by placing the solid in a known quantity of water in a container with measurement markings. Take the new volume and find the difference between this and the old volume. This is the volume of your irregularly shaped solid.
Finding the center of gravity of an irregularly shaped object can be done using the plumb line method.
square
batholiths
asteroid
Poikilocyte