The water sprinkled by the sprinkler forms a circular path. The area of this circular region would be determined by applying the formula for finding the area of a circle which is expressed as
Area = pi x radius^2
radius = distance from the sprinkler to the circumference of the circular path. Thus,
radius = 15
pi = 3.14
Area of circular region = 3.14 x 15^2 = 706.5
Area = 707 square feet