To find the width \( w \) of the rectangular prism, we can rearrange the volume formula \( V = lwh \) to solve for \( w \):
\[ w = \frac{V}{lh} \]
We are given:
- Volume \( V = 138.24 \) cubic inches
- Height \( h = 9.6 \) inches
- Length \( l = 3.2 \) inches
Now, we can substitute the values into the formula:
\[ w = \frac{138.24}{3.2 \times 9.6} \]
First, calculate \( 3.2 \times 9.6 \):
\[ 3.2 \times 9.6 = 30.72 \]
Now, substitute this back into the formula for width \( w \):
\[ w = \frac{138.24}{30.72} \]
Now perform the division:
\[ w \approx 4.5 \]
Therefore, the width of the rectangular prism is approximately 4.5 inches when rounded to the nearest tenth. Thus, the correct answer is:
4.5 inches