ANSWER
75 feet
Step-by-step 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:
![\begin{gathered} (1)/(20)\text{ = }(3.75)/(x) \\ \text{Cross}-\text{ multiply:} \\ 1\cdot\text{ x = 20 }\cdot\text{ 3.75} \\ x\text{ = 75 feet} \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/rsb6o6d6khcycienval3o8rmx59c7eovrp.png)
The actual length of the dinosaur is 75 feet.