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 area 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

The answer is 1808.64 ft²

To calculate area of square we need to find radius r. Radius is a half of a diameter:
r = d/2

The blueprint:
d = 18 cm
r = 18/2 = 9 cm

The blueprint has a scale of three centimeters to four feet. Actual radius r1 is:
3 cm : 4 ft = 18 cm : r1
After crossing the products:
r1 = 4 ft * 18 cm : 3 cm
r1 = 24 ft

The area of the circular base of the fountain is:
A = r1² * π
π = 3.14
r1 = 24 ft

A = 24² * 3.14
A = 1808.64 ft²