Elementary Math Help: Finding Volumes Using Cubes

Finding Volumes with Cubes

Volume is the amount of space that a 3-dimensional object takes up. You can figure out the volume of an object if you know how many cubic units it's made up of. A cubic unit is a cube-shaped block with equal length, width and height. If something is made up of 30 cubic units that are all equal in size, then you can say its volume is 30 cubic units.

Working with Cubic Units

Sometimes, you might be given a drawing of a 3-dimensional object that's made up of cubic units. To figure out the volume of an object like this, you can't physically count all of the cubic units. However, you can count the number of units that make up the object's length, height and width. If you multiply these three numbers together, that will tell you the total number of units that make up the object, which is its volume. For example, if you can see that an object is two units high, three units long and four units wide, then its volume is 24 cubic units (2 x 3 x 4 = 24).

You can also build objects with a given volume using cubic units. For instance, imagine that you have a set of 100 cube-shaped blocks, and you're asked to build two different objects, each with a volume of 50 cubic units. One of the objects could be just one unit high, two units wide and 25 units long. That would give it a volume of 50 cubic units, since 1 x 2 x 25 = 50. The second object could be five units high, five units wide and just two units long, since 5 x 5 x 2 = 50.

The objects could also be shaped irregularly. Their volumes would still be 50 cubic units as long as they were made up of 50 blocks each.

Types of Cubic Units

Cubic units can be any size; however, each edge must have the same length. Cubic units of specific sizes have special names. For instance, a cubic unit with edges of one centimeter is called a cubic centimeter. A unit that's one inch high, one inch wide and one inch long is called a cubic inch. The same is true for any other common unit of measure, including feet, yards and meters.