Answer: first option 392.699 square feet.
Explanation:
1) The shape of the sidewalk is an ring with exterior radius equal to the radious of the fountain + 5 feet and inner radius equal to the radius of the fountain.
2) The area of such ring is equal to the area of the outer circle less the area of the inner circle (the fountain)
Area of a circle = π × r²
Area of the outer circle: π (10ft + 5 ft)² = π (15 ft)² = 225 π ft²
Area of the inner circle = π (10ft)² = 100 π ft²
Area of the ring (sidewald) = 225π ft² - 100π ft² = 125π ft² = 392.699 ft²
Answer:
Replace l with 110 and w with 120
P = 2(110) + 2(120)
P = 220 + 240
P = 460 feet
