Question

A contractor is building the base of a circular fountain. On the blueprint, the base of the fountain has a diameter of 18 centimeters. The blueprint has a scale of three centimeters to four feet. What will be the actual ares of the base of the fountain, in square feet, after it is built? Round your answer to the nearest tenth of a square foot.

Answer 1

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!