Skill: Find volume of rectangular prisms

Volume measures the amount of three-dimensional space inside a rectangular prism. Imagine filling the prism with unit cubes. The cubes form equal layers, so:

$$V=l\times w\times h$$

The answer is written in cubic units, such as $\text{cm}^3$ or $\text{m}^3$.

Example: A rectangular prism is $4.5\text{ cm}$ long, $3\text{ cm}$ wide, and $2\text{ cm}$ high. Find its volume.

1. Identify the three dimensions:

$$l=4.5\text{ cm},\qquad w=3\text{ cm},\qquad h=2\text{ cm}$$

2. Substitute them into the formula:

$$V=4.5\times3\times2$$

3. Multiply:

$$4.5\times3=13.5$$ $$13.5\times2=27$$

4. Include cubic units:

$$\boxed{V=27\text{ cm}^3}$$

The volume is $27\text{ cm}^3$. This means the prism could hold $27$ unit cubes that each measure $1\text{ cm}$ on every side. Notice that volume uses all three dimensions and has cubic units, not square units.