Answer:
Area_lawn = 393.75 π ft^2
Step-by-step explanation:
Maximum radius : 30 feet
Minimum radius: 30 feet - 0.25*(30feet) = 22.5 feet
(25 percent reduction)
To find the area of lawn that can be watered, we just need to calculate the area for the maximum radius and the minimum radius, and then subtract them.
Since the sprinklers have a circular area:
Area = π*radius^2
Max area = π*(30 ft)^2 = 900π ft^2
Min area = π*(22.5 ft)^2 = 506.25π ft^2
Maximum area of lawn that can be watered by the sprinkler:
Area_lawn = Max area - Min area = 900π ft^2 -506.25π ft^2
Area_lawn = 393.75 π ft^2
