First off, neither a square or a rectangle have volume because neither have a a depth. A cube or a rectangular prism would though as they are 3 dimensional objects. The volume though mainly depends on its shape. A sphere for example is 4/3pir^3 which means (4/3) times the value of pi which is approximately 3.1415 times the value of the radius cubed. Other 3 dimensional objects have different formulas to determine their volume.
-- measure the length, width, and height of the object -- multiply the three numbers together -- the answer is the volume of the object
A ruler or tape measure.
There is not an instrument designed to measure the volume of a rectangular box. You would use a ruler or tape measure or similar to measure its linear dimensions and a brain to multiply them together.
If it is a cube (basically a square) or a rectangular prism multiply the top, the length, and the base.
It is called its volume.
Volume of rectangular prism: 5*5*20 = 500 cubic cm
Volume of an object is a measure of the space occupied by objects.
To do this, you will need to measure the length and the width and the height and your have your answer to the volume.
shiny teeth
It is easiest to measure the length, breadth and height and multiply them together.
Volume of a square = length*width*height
Volume is in 3D objects, so you should say volume for a cube. Area is for 2D objects, that is area for square. Volume for cube = side * side * side Area of square = side * side