Answer:
452.4 square feet
Finding the diameter:
Since there are 3 centimeters for every 4 feet, we need to divide 18 by 3
18 ÷ 3 = 6 which means the ratio is scaled up by 6 so we multiply 4 by 6
4 · 6 = 24 that means that the diameter of the base of the fountain is 24 feet
Finding the area:
Since the area of a circle is πr² we need to divide the diameter by 2 to get the radius(r)
24 ÷ 2 = 12 now we need to square 12 (which is multiplying it to itself ex. 5² is 5 · 5)
12 · 12 = 144 now we multiply it by π
π · 144 ≈ 452.38934 lastly we round it
452.4 square feet
Hope this helps!