Using proportions, it is found that the height of the lighthouse is of 84 ft.
The rule of three is:
5.25 feet - 8 feet
x feet - 128 feet
Applying cross multiplication:
[tex]8x = 5.25(128)[/tex]
[tex]x = \frac{5.25(128)}{8}[/tex]
[tex]x = 84[/tex]
The height of the lighthouse is of 84 ft.
A similar problem, which also uses proportions, is given at https://brainly.com/question/24372153