The circumference of the well is 47 ft and the area of the well in the drawing is 0.641 cm². If we say r is the radius of the circle on the drawing in centimeters and R is the actual radius of the well in feet, then:
47 = 2πR
0.641 = πr²
Solving for each:
R = 47 / (2π) ≈ 7.48 feet
r = √(0.641 / π) ≈ 0.452 cm
The scale is the ratio of R / r:
R / r = (7.48 ft) / (0.452 cm) = 16.6 ft/cm
So 1 cm = 16.6 ft.
This isn't one of the options. Are you sure you copied the problem correctly?
Maybe you meant that the circumference is 4π feet, and the area is 0.64π cm². If so: