Answer
$48\text{ inches}$
Work Step by Step
Use the conversion rate $1 \text{ft} = 12 \text{ inches}$ by multiplying $\frac{12\text{ inches}}{1\text{ ft}}$ to obtain:
$\require{cancel}
4\text{ ft}
\\= 4\text{ ft} \cdot \frac{12\text{ in}}{1\text{ ft}}
\\= 4\cancel{\text{ ft}} \cdot \frac{12\text{ in}}{1\cancel{\text{ ft}}}
\\=48\text{ inches}$
