1. **State the problem:** We are given a rectangular prism with length $9$ inches, width $5$ inches, and an unknown height. We need to find the height given the volume or find the volume if height is given. 2. **Formula for volume of a rectangular prism:** $$V = \text{length} \times \text{width} \times \text{height}$$ 3. **Explanation:** The volume is the amount of space inside the prism. To find the height, if volume is known, rearrange the formula: $$\text{height} = \frac{V}{\text{length} \times \text{width}}$$ 4. **Intermediate work:** Suppose the volume $V$ is given or needs to be found. For example, if volume is $270$ cubic inches: $$\text{height} = \frac{270}{9 \times 5}$$ $$= \frac{270}{45}$$ $$= \cancel{\frac{270}{45}}6$$ 5. **Answer:** The height is $6$ inches. If the height is unknown and volume is not given, you need either the volume or height to solve the problem.