Given :
The scale of the model is : 1 inch = 4 feet
The height of the actual T-Rex = 20 feet
Let the height of the model = x
Using the ratio and the proportional
so,
[tex]\begin{gathered} x\colon20=1\colon4 \\ \\ \frac{x}{20}=\frac{1}{4} \\ \\ x=20\cdot\frac{1}{4}=5 \end{gathered}[/tex]