ANSWER
75 feet
EXPLANATION
The scale factor means that the ratio of the model to the actual size of the dinosaur is 1 : 20.
The model is 3.75 feet long.
Let the actual length of the dinosaur be x.
So, it means that:
[tex]\begin{gathered} \frac{1}{20}\text{ = }\frac{3.75}{x} \\ \text{Cross}-\text{ multiply:} \\ 1\cdot\text{ x = 20 }\cdot\text{ 3.75} \\ x\text{ = 75 feet} \end{gathered}[/tex]The actual length of the dinosaur is 75 feet.
