Answer:
45 feet.
Step-by-step explanation:
Given that a model of a lighthouse has diameter 8 inches and height 18 inches, and the actual diameter of the lighthouse is 20 feet, in order to find its actual height, the following calculation has to be made:
20 feet = 240 inches
240 / 8 = 30
Scale ratio: 1:30
18 x 30 = 540
540 inches = 45 feet
Therefore, the actual height of the lighthouse is 45 feet.
